diff --git a/src/validation.cpp b/src/validation.cpp
index 41702d568..6ed0c9e51 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -507,7 +507,7 @@ int GetUTXOConfirmations(const COutPoint& outpoint)
 }
 
 
-bool CheckTransaction(const CTransaction& tx, CValidationState &state, bool fCheckDuplicateInputs)
+bool CheckTransaction(const CTransaction& tx, CValidationState &state)
 {
     // Basic checks that don't depend on any context
     if (tx.vin.empty())
@@ -531,14 +531,12 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state, bool fChe
             return state.DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge");
     }
 
-    // Check for duplicate inputs - note that this check is slow so we skip it in CheckBlock
-    if (fCheckDuplicateInputs) {
-        std::set<COutPoint> vInOutPoints;
-        for (const auto& txin : tx.vin)
-        {
-            if (!vInOutPoints.insert(txin.prevout).second)
-                return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
-        }
+    // Check for duplicate inputs
+    std::set<COutPoint> vInOutPoints;
+    for (const auto& txin : tx.vin)
+    {
+        if (!vInOutPoints.insert(txin.prevout).second)
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
     }
 
     if (tx.IsCoinBase())
@@ -3366,7 +3364,7 @@ bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::P
 
     // Check transactions
     for (const auto& tx : block.vtx)
-        if (!CheckTransaction(*tx, state, true))
+        if (!CheckTransaction(*tx, state))
             return state.Invalid(false, state.GetRejectCode(), state.GetRejectReason(),
                                  strprintf("Transaction check failed (tx hash %s) %s", tx->GetHash().ToString(), state.GetDebugMessage()));
 
diff --git a/src/validation.h b/src/validation.h
index 18d7b8b88..6ddb205c3 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -386,7 +386,7 @@ void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight);
 /** Transaction validation functions */
 
 /** Context-independent validity checks */
-bool CheckTransaction(const CTransaction& tx, CValidationState& state, bool fCheckDuplicateInputs=true);
+bool CheckTransaction(const CTransaction& tx, CValidationState& state);
 
 namespace Consensus {