diff --git a/ethereumj-core/src/main/java/org/ethereum/core/BlockchainImpl.java b/ethereumj-core/src/main/java/org/ethereum/core/BlockchainImpl.java
index b75f8b43..d24aa111 100644
--- a/ethereumj-core/src/main/java/org/ethereum/core/BlockchainImpl.java
+++ b/ethereumj-core/src/main/java/org/ethereum/core/BlockchainImpl.java
@@ -190,7 +190,7 @@ public class BlockchainImpl implements Blockchain {
 			for (BlockHeader uncle : block.getUncleList()) {
 				repository.addBalance(uncle.getCoinbase(), Block.UNCLE_REWARD);
 			}
-			totalBlockReward.add(Block.INCLUSION_REWARD
+			totalBlockReward = totalBlockReward.add(Block.INCLUSION_REWARD
 					.multiply(BigInteger.valueOf(block.getUncleList().size())));
 		}
 		repository.addBalance(block.getCoinbase(), totalBlockReward);