diff --git a/src/consensus/consensus.h b/src/consensus/consensus.h
--- a/src/consensus/consensus.h
+++ b/src/consensus/consensus.h
@@ -16,14 +16,20 @@
 static const uint64_t LEGACY_MAX_BLOCK_SIZE = ONE_MEGABYTE;
 /** Default setting for maximum allowed size for a block, in bytes */
 static const uint64_t DEFAULT_MAX_BLOCK_SIZE = 32 * ONE_MEGABYTE;
-/** The maximum allowed number of signature check operations per MB in a block
- * (network rule) */
+/**
+ * The maximum allowed number of signature check operations per MB in a block
+ * (network rule).
+ */
 static const int64_t MAX_BLOCK_SIGOPS_PER_MB = 20000;
 /** allowed number of signature check operations per transaction. */
 static const uint64_t MAX_TX_SIGOPS_COUNT = 20000;
-/** Coinbase transaction outputs can only be spent after this number of new
- * blocks (network rule) */
+/**
+ * Coinbase transaction outputs can only be spent after this number of new
+ * blocks (network rule).
+ */
 static const int COINBASE_MATURITY = 100;
+/** Activation time for P2SH (April 1st 2012) */
+static const int64_t P2SH_ACTIVATION_TIME = 1333234914;
 
 /** Flags for nSequence and nLockTime locks */
 enum {
diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -292,7 +292,7 @@
         pblock->nNonce = blockinfo[i].nonce;
         std::shared_ptr<const CBlock> shared_pblock =
             std::make_shared<const CBlock>(*pblock);
-        BOOST_CHECK(ProcessNewBlock(GetConfig(), shared_pblock, true, nullptr));
+        BOOST_CHECK(ProcessNewBlock(config, shared_pblock, true, nullptr));
         pblock->hashPrevBlock = pblock->GetHash();
     }
 
@@ -357,8 +357,10 @@
     tx.vin[0].scriptSig = CScript();
     // 18 * (520char + DROP) + OP_1 = 9433 bytes
     std::vector<uint8_t> vchData(520);
-    for (unsigned int i = 0; i < 18; ++i)
+    for (unsigned int i = 0; i < 18; ++i) {
         tx.vin[0].scriptSig << vchData << OP_DROP;
+    }
+
     tx.vin[0].scriptSig << OP_1;
     tx.vin[0].prevout.hash = txFirst[0]->GetId();
     tx.vout[0].nValue = BLOCKSUBSIDY;
@@ -423,6 +425,16 @@
     mempool.clear();
 
     // Invalid (pre-p2sh) txn in mempool, template creation fails.
+    std::array<int64_t, CBlockIndex::nMedianTimeSpan> times;
+    for (int i = 0; i < CBlockIndex::nMedianTimeSpan; i++) {
+        // Trick the MedianTimePast.
+        times[i] = chainActive.Tip()
+                       ->GetAncestor(chainActive.Tip()->nHeight - i)
+                       ->nTime;
+        chainActive.Tip()->GetAncestor(chainActive.Tip()->nHeight - i)->nTime =
+            P2SH_ACTIVATION_TIME;
+    }
+
     tx.vin[0].prevout.hash = txFirst[0]->GetId();
     tx.vin[0].prevout.n = 0;
     tx.vin[0].scriptSig = CScript() << OP_1;
@@ -444,6 +456,11 @@
     BOOST_CHECK_THROW(BlockAssembler(config).CreateNewBlock(scriptPubKey),
                       std::runtime_error);
     mempool.clear();
+    for (int i = 0; i < CBlockIndex::nMedianTimeSpan; i++) {
+        // Restore the MedianTimePast.
+        chainActive.Tip()->GetAncestor(chainActive.Tip()->nHeight - i)->nTime =
+            times[i];
+    }
 
     // Double spend txn pair in mempool, template creation fails.
     tx.vin[0].prevout.hash = txFirst[0]->GetId();
diff --git a/src/validation.cpp b/src/validation.cpp
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1908,9 +1908,9 @@
     const Consensus::Params &consensusparams =
         config.GetChainParams().GetConsensus();
 
-    // BIP16 didn't become active until Apr 1 2012
-    int64_t nBIP16SwitchTime = 1333238400;
-    bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
+    // P2SH didn't become active until Apr 1 2012
+    bool fStrictPayToScriptHash =
+        (pindex->pprev->GetMedianTimePast() >= P2SH_ACTIVATION_TIME);
 
     uint32_t flags =
         fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
@@ -3361,8 +3361,9 @@
                                           pos.nPos);
                     fclose(file);
                 }
-            } else
+            } else {
                 return state.Error("out of disk space");
+            }
         }
     }
 
@@ -3950,7 +3951,9 @@
                      bool fForceProcessing, bool *fNewBlock) {
     {
         CBlockIndex *pindex = nullptr;
-        if (fNewBlock) *fNewBlock = false;
+        if (fNewBlock) {
+            *fNewBlock = false;
+        }
 
         const CChainParams &chainparams = config.GetChainParams();