diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -640,6 +640,7 @@
 
     std::set<int64_t> setInternalKeyPool;
     std::set<int64_t> setExternalKeyPool;
+    int64_t m_max_keypool_index;
 
     int64_t nTimeFirstKey;
 
@@ -684,12 +685,13 @@
         }
     }
 
-    void LoadKeyPool(int nIndex, const CKeyPool &keypool) {
+    void LoadKeyPool(int64_t nIndex, const CKeyPool &keypool) {
         if (keypool.fInternal) {
             setInternalKeyPool.insert(nIndex);
         } else {
             setExternalKeyPool.insert(nIndex);
         }
+        m_max_keypool_index = std::max(m_max_keypool_index, nIndex);
 
         // If no metadata exists yet, create a default with the pool key's
         // creation time. Note that this may be overwritten by actually stored
@@ -729,6 +731,7 @@
         nAccountingEntryNumber = 0;
         nNextResend = 0;
         nLastResend = 0;
+        m_max_keypool_index = 0;
         nTimeFirstKey = 0;
         fBroadcastTransactions = false;
     }
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -3293,28 +3293,25 @@
     bool internal = false;
     CWalletDB walletdb(*dbw);
     for (int64_t i = missingInternal + missingExternal; i--;) {
-        int64_t nEnd = 1;
         if (i < missingInternal) {
             internal = true;
         }
 
-        if (!setInternalKeyPool.empty()) {
-            nEnd = *(setInternalKeyPool.rbegin()) + 1;
-        }
-        if (!setExternalKeyPool.empty()) {
-            nEnd = std::max(nEnd, *(setExternalKeyPool.rbegin()) + 1);
-        }
+        // How in the hell did you use so many keys?
+        assert(m_max_keypool_index < std::numeric_limits<int64_t>::max());
+        int64_t index = ++m_max_keypool_index;
 
         if (!walletdb.WritePool(
-                nEnd, CKeyPool(GenerateNewKey(walletdb, internal), internal))) {
+                index,
+                CKeyPool(GenerateNewKey(walletdb, internal), internal))) {
             throw std::runtime_error(std::string(__func__) +
                                      ": writing generated key failed");
         }
 
         if (internal) {
-            setInternalKeyPool.insert(nEnd);
+            setInternalKeyPool.insert(index);
         } else {
-            setExternalKeyPool.insert(nEnd);
+            setExternalKeyPool.insert(index);
         }
     }
     if (missingInternal + missingExternal > 0) {