diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index d53dcfdb567..bb01b42c164 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -133,6 +133,9 @@ class CMainParams : public CChainParams {
         consensus.vUpgrades[Consensus::UPGRADE_SAPLING].nProtocolVersion = 170007;
         consensus.vUpgrades[Consensus::UPGRADE_SAPLING].nActivationHeight = Consensus::NetworkUpgrade::NO_ACTIVATION_HEIGHT;
 
+        // The best chain should have at least this much work.
+        consensus.nMinimumChainWork = uint256S("0x00000000000000000000000000000000000000000000000000281b32ff3198a1");
+        
         /**
          * The message start string is designed to be unlikely to occur in normal data.
          * The characters are rarely used upper ASCII, not valid as UTF-8, and produce
@@ -385,6 +388,9 @@ class CTestNetParams : public CChainParams {
         consensus.vUpgrades[Consensus::UPGRADE_SAPLING].nProtocolVersion = 170007;
         consensus.vUpgrades[Consensus::UPGRADE_SAPLING].nActivationHeight = 280000;
 
+        // The best chain should have at least this much work.
+        consensus.nMinimumChainWork = uint256S("0x00000000000000000000000000000000000000000000000000000001d0c4d9cd");
+        
         pchMessageStart[0] = 0x5A;
         pchMessageStart[1] = 0x1F;
         pchMessageStart[2] = 0x7E;
@@ -480,6 +486,9 @@ class CRegTestParams : public CChainParams {
             Consensus::NetworkUpgrade::NO_ACTIVATION_HEIGHT;
         coinbaseMaturity = 1;
 
+        // The best chain should have at least this much work.
+        consensus.nMinimumChainWork = uint256S("0x00");
+        
         pchMessageStart[0] = 0xaa;
         pchMessageStart[1] = 0x8e;
         pchMessageStart[2] = 0xf3;
diff --git a/src/consensus/params.h b/src/consensus/params.h
index e6566d21193..d562cc2bd29 100644
--- a/src/consensus/params.h
+++ b/src/consensus/params.h
@@ -141,6 +141,7 @@ struct Params {
     int64_t MaxActualTimespan() const { return (AveragingWindowTimespan() * (100 + nPowMaxAdjustDown)) / 100; }
     void SetSaplingHeight(int32_t height) { vUpgrades[Consensus::UPGRADE_SAPLING].nActivationHeight = height; }
     void SetOverwinterHeight(int32_t height) { vUpgrades[Consensus::UPGRADE_OVERWINTER].nActivationHeight = height; }
+    uint256 nMinimumChainWork;
 };
 
 } // namespace Consensus
diff --git a/src/main.cpp b/src/main.cpp
index f912d9cdccb..1a9fe714612 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2486,6 +2486,11 @@ bool IsInitialBlockDownload()
     {
         return true;
     }
+    if (false && ptr->nChainWork < UintToArith256(chainParams.GetConsensus().nMinimumChainWork))   // MinimumChainWork disabled
+    {
+        fprintf(stderr,"nChainWork insufficient in IsInitialDownload\n");
+        return true;
+    }
     bool state = ((chainActive.Height() < ptr->nHeight - 24*60) ||
              ptr->GetBlockTime() < (GetTime() - nMaxTipAge));
     if ( KOMODO_INSYNC != 0 )