diff --git a/chain/src/pipe.rs b/chain/src/pipe.rs
index 684b1293c..19f882f9d 100644
--- a/chain/src/pipe.rs
+++ b/chain/src/pipe.rs
@@ -167,7 +167,6 @@ fn validate_header(b: &Block, ctx: &mut BlockContext) -> Result<(), Error> {
 
 /// Fully validate the block content.
 fn validate_block(b: &Block, ctx: &mut BlockContext) -> Result<(), Error> {
-	// TODO check tx merkle tree
 	let curve = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
 	try!(b.verify(&curve).map_err(&Error::InvalidBlockProof));
 	// TODO check every input exists
diff --git a/core/src/core/block.rs b/core/src/core/block.rs
index 97c210544..afdea2289 100644
--- a/core/src/core/block.rs
+++ b/core/src/core/block.rs
@@ -350,6 +350,7 @@ impl Block {
 	pub fn verify(&self, secp: &Secp256k1) -> Result<(), secp::Error> {
 		// sum all inputs and outs commitments
 		let io_sum = try!(self.sum_commitments(secp));
+
 		// sum all proofs commitments
 		let proof_commits = map_vec!(self.proofs, |proof| proof.remainder);
 		let proof_sum = try!(secp.commit_sum(proof_commits, vec![]));
@@ -364,6 +365,14 @@ impl Block {
 		for proof in &self.proofs {
 			try!(proof.verify(secp));
 		}
+
+		// verify the transaction Merkle root
+		let tx_merkle = merkle_inputs_outputs(&self.inputs, &self.outputs);
+		if tx_merkle != self.header.tx_merkle {
+			// TODO more specific error
+			return Err(secp::Error::IncorrectCommitSum);
+		}
+
 		Ok(())
 	}