diff --git a/src/addrman.h b/src/addrman.h
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -13,9 +13,9 @@
 #include "timedata.h"
 #include "util.h"
 
+#include <cstdint>
 #include <map>
 #include <set>
-#include <stdint.h>
 #include <vector>
 
 /**
diff --git a/src/bench/Examples.cpp b/src/bench/Examples.cpp
--- a/src/bench/Examples.cpp
+++ b/src/bench/Examples.cpp
@@ -17,7 +17,7 @@
 BENCHMARK(Sleep100ms);
 
 // Extremely fast-running benchmark:
-#include <math.h>
+#include <cmath>
 
 volatile double sum = 0.0; // volatile, global so not optimized away
 
diff --git a/src/bench/perf.h b/src/bench/perf.h
--- a/src/bench/perf.h
+++ b/src/bench/perf.h
@@ -6,7 +6,7 @@
 #ifndef H_PERF
 #define H_PERF
 
-#include <stdint.h>
+#include <cstdint>
 
 #if defined(__i386__)
 
diff --git a/src/bitcoind.cpp b/src/bitcoind.cpp
--- a/src/bitcoind.cpp
+++ b/src/bitcoind.cpp
@@ -24,7 +24,7 @@
 #include <boost/filesystem.hpp>
 #include <boost/thread.hpp>
 
-#include <stdio.h>
+#include <cstdio>
 
 /* Introduction text for doxygen: */
 
diff --git a/src/chainparamsbase.cpp b/src/chainparamsbase.cpp
--- a/src/chainparamsbase.cpp
+++ b/src/chainparamsbase.cpp
@@ -8,7 +8,7 @@
 #include "tinyformat.h"
 #include "util.h"
 
-#include <assert.h>
+#include <cassert>
 
 const std::string CBaseChainParams::MAIN = "main";
 const std::string CBaseChainParams::TESTNET = "test";
diff --git a/src/compat/endian.h b/src/compat/endian.h
--- a/src/compat/endian.h
+++ b/src/compat/endian.h
@@ -9,7 +9,7 @@
 #include "config/bitcoin-config.h"
 #endif
 
-#include <stdint.h>
+#include <cstdint>
 
 #include "compat/byteswap.h"
 
diff --git a/src/consensus/merkle.h b/src/consensus/merkle.h
--- a/src/consensus/merkle.h
+++ b/src/consensus/merkle.h
@@ -5,7 +5,7 @@
 #ifndef BITCOIN_MERKLE
 #define BITCOIN_MERKLE
 
-#include <stdint.h>
+#include <cstdint>
 #include <vector>
 
 #include "primitives/block.h"
diff --git a/src/crypto/aes.cpp b/src/crypto/aes.cpp
--- a/src/crypto/aes.cpp
+++ b/src/crypto/aes.cpp
@@ -5,8 +5,8 @@
 #include "aes.h"
 #include "crypto/common.h"
 
-#include <assert.h>
-#include <string.h>
+#include <cassert>
+#include <cstring>
 
 extern "C" {
 #include "crypto/ctaes/ctaes.c"
diff --git a/src/crypto/common.h b/src/crypto/common.h
--- a/src/crypto/common.h
+++ b/src/crypto/common.h
@@ -9,8 +9,8 @@
 #include "bitcoin-config.h"
 #endif
 
-#include <stdint.h>
-#include <string.h>
+#include <cstdint>
+#include <cstring>
 
 #include "compat/endian.h"
 
diff --git a/src/crypto/hmac_sha256.h b/src/crypto/hmac_sha256.h
--- a/src/crypto/hmac_sha256.h
+++ b/src/crypto/hmac_sha256.h
@@ -7,8 +7,8 @@
 
 #include "crypto/sha256.h"
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstdint>
+#include <cstdlib>
 
 /** A hasher class for HMAC-SHA-512. */
 class CHMAC_SHA256 {
diff --git a/src/crypto/hmac_sha256.cpp b/src/crypto/hmac_sha256.cpp
--- a/src/crypto/hmac_sha256.cpp
+++ b/src/crypto/hmac_sha256.cpp
@@ -4,7 +4,7 @@
 
 #include "crypto/hmac_sha256.h"
 
-#include <string.h>
+#include <cstring>
 
 CHMAC_SHA256::CHMAC_SHA256(const unsigned char *key, size_t keylen) {
     unsigned char rkey[64];
diff --git a/src/crypto/hmac_sha512.h b/src/crypto/hmac_sha512.h
--- a/src/crypto/hmac_sha512.h
+++ b/src/crypto/hmac_sha512.h
@@ -7,8 +7,8 @@
 
 #include "crypto/sha512.h"
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstdint>
+#include <cstdlib>
 
 /** A hasher class for HMAC-SHA-512. */
 class CHMAC_SHA512 {
diff --git a/src/crypto/hmac_sha512.cpp b/src/crypto/hmac_sha512.cpp
--- a/src/crypto/hmac_sha512.cpp
+++ b/src/crypto/hmac_sha512.cpp
@@ -4,7 +4,7 @@
 
 #include "crypto/hmac_sha512.h"
 
-#include <string.h>
+#include <cstring>
 
 CHMAC_SHA512::CHMAC_SHA512(const unsigned char *key, size_t keylen) {
     unsigned char rkey[128];
diff --git a/src/crypto/ripemd160.h b/src/crypto/ripemd160.h
--- a/src/crypto/ripemd160.h
+++ b/src/crypto/ripemd160.h
@@ -5,8 +5,8 @@
 #ifndef BITCOIN_CRYPTO_RIPEMD160_H
 #define BITCOIN_CRYPTO_RIPEMD160_H
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstdint>
+#include <cstdlib>
 
 /** A hasher class for RIPEMD-160. */
 class CRIPEMD160 {
diff --git a/src/crypto/ripemd160.cpp b/src/crypto/ripemd160.cpp
--- a/src/crypto/ripemd160.cpp
+++ b/src/crypto/ripemd160.cpp
@@ -6,7 +6,7 @@
 
 #include "crypto/common.h"
 
-#include <string.h>
+#include <cstring>
 
 // Internal implementation code.
 namespace {
diff --git a/src/crypto/sha1.h b/src/crypto/sha1.h
--- a/src/crypto/sha1.h
+++ b/src/crypto/sha1.h
@@ -5,8 +5,8 @@
 #ifndef BITCOIN_CRYPTO_SHA1_H
 #define BITCOIN_CRYPTO_SHA1_H
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstdint>
+#include <cstdlib>
 
 /** A hasher class for SHA1. */
 class CSHA1 {
diff --git a/src/crypto/sha1.cpp b/src/crypto/sha1.cpp
--- a/src/crypto/sha1.cpp
+++ b/src/crypto/sha1.cpp
@@ -6,7 +6,7 @@
 
 #include "crypto/common.h"
 
-#include <string.h>
+#include <cstring>
 
 // Internal implementation code.
 namespace {
diff --git a/src/crypto/sha256.h b/src/crypto/sha256.h
--- a/src/crypto/sha256.h
+++ b/src/crypto/sha256.h
@@ -5,8 +5,8 @@
 #ifndef BITCOIN_CRYPTO_SHA256_H
 #define BITCOIN_CRYPTO_SHA256_H
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstdint>
+#include <cstdlib>
 
 /** A hasher class for SHA-256. */
 class CSHA256 {
diff --git a/src/crypto/sha256.cpp b/src/crypto/sha256.cpp
--- a/src/crypto/sha256.cpp
+++ b/src/crypto/sha256.cpp
@@ -6,7 +6,7 @@
 
 #include "crypto/common.h"
 
-#include <string.h>
+#include <cstring>
 
 // Internal implementation code.
 namespace {
diff --git a/src/crypto/sha512.h b/src/crypto/sha512.h
--- a/src/crypto/sha512.h
+++ b/src/crypto/sha512.h
@@ -5,8 +5,8 @@
 #ifndef BITCOIN_CRYPTO_SHA512_H
 #define BITCOIN_CRYPTO_SHA512_H
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstdint>
+#include <cstdlib>
 
 /** A hasher class for SHA-512. */
 class CSHA512 {
diff --git a/src/crypto/sha512.cpp b/src/crypto/sha512.cpp
--- a/src/crypto/sha512.cpp
+++ b/src/crypto/sha512.cpp
@@ -6,7 +6,7 @@
 
 #include "crypto/common.h"
 
-#include <string.h>
+#include <cstring>
 
 // Internal implementation code.
 namespace {
diff --git a/src/dbwrapper.cpp b/src/dbwrapper.cpp
--- a/src/dbwrapper.cpp
+++ b/src/dbwrapper.cpp
@@ -9,11 +9,11 @@
 
 #include <boost/filesystem.hpp>
 
+#include <cstdint>
 #include <leveldb/cache.h>
 #include <leveldb/env.h>
 #include <leveldb/filter_policy.h>
 #include <memenv.h>
-#include <stdint.h>
 
 static leveldb::Options GetOptions(size_t nCacheSize) {
     leveldb::Options options;
diff --git a/src/httpserver.h b/src/httpserver.h
--- a/src/httpserver.h
+++ b/src/httpserver.h
@@ -5,8 +5,8 @@
 #ifndef BITCOIN_HTTPSERVER_H
 #define BITCOIN_HTTPSERVER_H
 
+#include <cstdint>
 #include <functional>
-#include <stdint.h>
 #include <string>
 
 static const int DEFAULT_HTTP_THREADS = 4;
diff --git a/src/httpserver.cpp b/src/httpserver.cpp
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -12,9 +12,9 @@
 #include "ui_interface.h"
 #include "util.h"
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
 
 #include <future>
 #include <signal.h>
diff --git a/src/init.cpp b/src/init.cpp
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -44,9 +44,9 @@
 #include "wallet/wallet.h"
 #endif
 #include "warnings.h"
+#include <cstdint>
+#include <cstdio>
 #include <memory>
-#include <stdint.h>
-#include <stdio.h>
 
 #ifndef WIN32
 #include <signal.h>
diff --git a/src/limitedmap.h b/src/limitedmap.h
--- a/src/limitedmap.h
+++ b/src/limitedmap.h
@@ -5,7 +5,7 @@
 #ifndef BITCOIN_LIMITEDMAP_H
 #define BITCOIN_LIMITEDMAP_H
 
-#include <assert.h>
+#include <cassert>
 #include <map>
 
 /**
diff --git a/src/protocol.h b/src/protocol.h
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -15,7 +15,7 @@
 #include "uint256.h"
 #include "version.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <string>
 
 /** Message header.
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -37,7 +37,7 @@
 #include "wallet/wallet.h"
 #endif
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <boost/filesystem/operations.hpp>
 #include <boost/thread.hpp>
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -19,7 +19,7 @@
 #include "util.h"
 #include "validation.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <QDebug>
 #include <QTimer>
diff --git a/src/qt/notificator.cpp b/src/qt/notificator.cpp
--- a/src/qt/notificator.cpp
+++ b/src/qt/notificator.cpp
@@ -16,7 +16,7 @@
 #include <QVariant>
 #ifdef USE_DBUS
 #include <QtDBus>
-#include <stdint.h>
+#include <cstdint>
 #endif
 // Include ApplicationServices.h after QtDbus to avoid redefinition of check().
 // This affects at least OSX 10.6. See /usr/include/AssertMacros.h for details.
diff --git a/src/qt/utilitydialog.cpp b/src/qt/utilitydialog.cpp
--- a/src/qt/utilitydialog.cpp
+++ b/src/qt/utilitydialog.cpp
@@ -21,7 +21,7 @@
 #include "init.h"
 #include "util.h"
 
-#include <stdio.h>
+#include <cstdio>
 
 #include <QCloseEvent>
 #include <QLabel>
diff --git a/src/script/bitcoinconsensus.h b/src/script/bitcoinconsensus.h
--- a/src/script/bitcoinconsensus.h
+++ b/src/script/bitcoinconsensus.h
@@ -6,7 +6,7 @@
 #ifndef BITCOIN_BITCOINCONSENSUS_H
 #define BITCOIN_BITCOINCONSENSUS_H
 
-#include <stdint.h>
+#include <cstdint>
 
 #if defined(BUILD_BITCOIN_INTERNAL) && defined(HAVE_CONFIG_H)
 #include "config/bitcoin-config.h"
diff --git a/src/script/script.h b/src/script/script.h
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -9,12 +9,12 @@
 #include "crypto/common.h"
 #include "prevector.h"
 
-#include <assert.h>
+#include <cassert>
 #include <climits>
+#include <cstdint>
+#include <cstring>
 #include <limits>
 #include <stdexcept>
-#include <stdint.h>
-#include <string.h>
 #include <string>
 #include <vector>
 
diff --git a/src/streams.h b/src/streams.h
--- a/src/streams.h
+++ b/src/streams.h
@@ -10,14 +10,14 @@
 #include "support/allocators/zeroafterfree.h"
 
 #include <algorithm>
-#include <assert.h>
+#include <cassert>
+#include <cstdint>
+#include <cstdio>
+#include <cstring>
 #include <ios>
 #include <limits>
 #include <map>
 #include <set>
-#include <stdint.h>
-#include <stdio.h>
-#include <string.h>
 #include <string>
 #include <utility>
 #include <vector>
diff --git a/src/support/lockedpool.cpp b/src/support/lockedpool.cpp
--- a/src/support/lockedpool.cpp
+++ b/src/support/lockedpool.cpp
@@ -20,7 +20,7 @@
 #endif
 #include <windows.h>
 #else
-#include <limits.h>       // for PAGESIZE
+#include <climits>        // for PAGESIZE
 #include <sys/mman.h>     // for mmap
 #include <sys/resource.h> // for getrlimit
 #include <unistd.h>       // for sysconf
@@ -204,7 +204,7 @@
 
 PosixLockedPageAllocator::PosixLockedPageAllocator() {
 // Determine system page size in bytes
-#if defined(PAGESIZE) // defined in limits.h
+#if defined(PAGESIZE) // defined in climits
     page_size = PAGESIZE;
 #else // assume some POSIX OS
     page_size = sysconf(_SC_PAGESIZE);
diff --git a/src/test/arith_uint256_tests.cpp b/src/test/arith_uint256_tests.cpp
--- a/src/test/arith_uint256_tests.cpp
+++ b/src/test/arith_uint256_tests.cpp
@@ -8,10 +8,10 @@
 #include "version.h"
 #include <boost/test/unit_test.hpp>
 #include <cmath>
+#include <cstdint>
 #include <iomanip>
 #include <limits>
 #include <sstream>
-#include <stdint.h>
 #include <string>
 
 BOOST_FIXTURE_TEST_SUITE(arith_uint256_tests, BasicTestingSetup)
diff --git a/src/test/compress_tests.cpp b/src/test/compress_tests.cpp
--- a/src/test/compress_tests.cpp
+++ b/src/test/compress_tests.cpp
@@ -6,7 +6,7 @@
 #include "test/test_bitcoin.h"
 #include "util.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <boost/test/unit_test.hpp>
 
diff --git a/src/test/raii_event_tests.cpp b/src/test/raii_event_tests.cpp
--- a/src/test/raii_event_tests.cpp
+++ b/src/test/raii_event_tests.cpp
@@ -9,8 +9,8 @@
 // boost::test doesn't seem to make that practical (at least not in versions
 // available with common distros)
 
+#include <cstdlib>
 #include <map>
-#include <stdlib.h>
 
 #include "support/events.h"
 
diff --git a/src/test/scriptnum10.h b/src/test/scriptnum10.h
--- a/src/test/scriptnum10.h
+++ b/src/test/scriptnum10.h
@@ -6,11 +6,11 @@
 #ifndef BITCOIN_TEST_SCRIPTNUM10_H
 #define BITCOIN_TEST_SCRIPTNUM10_H
 
-#include "assert.h"
 #include <algorithm>
+#include <cassert>
+#include <cstdint>
 #include <limits>
 #include <stdexcept>
-#include <stdint.h>
 #include <string>
 #include <vector>
 
diff --git a/src/test/scriptnum_tests.cpp b/src/test/scriptnum_tests.cpp
--- a/src/test/scriptnum_tests.cpp
+++ b/src/test/scriptnum_tests.cpp
@@ -7,8 +7,8 @@
 #include "test/test_bitcoin.h"
 
 #include <boost/test/unit_test.hpp>
-#include <limits.h>
-#include <stdint.h>
+#include <climits>
+#include <cstdint>
 
 BOOST_FIXTURE_TEST_SUITE(scriptnum_tests, BasicTestingSetup)
 
diff --git a/src/test/test_bitcoin_fuzzy.cpp b/src/test/test_bitcoin_fuzzy.cpp
--- a/src/test/test_bitcoin_fuzzy.cpp
+++ b/src/test/test_bitcoin_fuzzy.cpp
@@ -20,7 +20,7 @@
 #include "undo.h"
 #include "version.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <unistd.h>
 
 #include <algorithm>
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -12,7 +12,7 @@
 #include "utilmoneystr.h"
 #include "utilstrencodings.h"
 
-#include <stdint.h>
+#include <cstdint>
 #include <vector>
 
 #include <boost/test/unit_test.hpp>
diff --git a/src/torcontrol.cpp b/src/torcontrol.cpp
--- a/src/torcontrol.cpp
+++ b/src/torcontrol.cpp
@@ -9,9 +9,9 @@
 #include "util.h"
 #include "utilstrencodings.h"
 
+#include <cstdlib>
 #include <deque>
 #include <set>
-#include <stdlib.h>
 #include <vector>
 
 #include <boost/algorithm/string/classification.hpp>
diff --git a/src/txdb.cpp b/src/txdb.cpp
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -10,7 +10,7 @@
 #include "pow.h"
 #include "uint256.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <boost/thread.hpp>
 
diff --git a/src/validation.h b/src/validation.h
--- a/src/validation.h
+++ b/src/validation.h
@@ -20,10 +20,10 @@
 #include "versionbits.h"
 
 #include <algorithm>
+#include <cstdint>
 #include <exception>
 #include <map>
 #include <set>
-#include <stdint.h>
 #include <string>
 #include <utility>
 #include <vector>
diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -11,7 +11,7 @@
 #include "util.h"
 #include "utilstrencodings.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 #ifndef WIN32
 #include <sys/stat.h>