diff --git a/core/src/main/java/org/bitcoinj/core/Block.java b/core/src/main/java/org/bitcoinj/core/Block.java
index f1662dab..942d1efd 100644
--- a/core/src/main/java/org/bitcoinj/core/Block.java
+++ b/core/src/main/java/org/bitcoinj/core/Block.java
@@ -92,7 +92,7 @@ public class Block extends Message {
     // Fields defined as part of the protocol format.
     private long version;
     private Sha256Hash prevBlockHash;
-    private Sha256Hash merkleRoot;
+    private Sha256Hash merkleRoot, witnessRoot;
     private long time;
     private long difficultyTarget; // "nBits"
     private long nonce;
@@ -484,11 +484,12 @@ public class Block extends Message {
             s.append(" (").append(bips).append(')');
         s.append('\n');
         s.append("   previous block: ").append(getPrevBlockHash()).append("\n");
-        s.append("   merkle root: ").append(getMerkleRoot()).append("\n");
         s.append("   time: ").append(time).append(" (").append(Utils.dateTimeFormat(time * 1000)).append(")\n");
         s.append("   difficulty target (nBits): ").append(difficultyTarget).append("\n");
         s.append("   nonce: ").append(nonce).append("\n");
         if (transactions != null && transactions.size() > 0) {
+            s.append("   merkle root: ").append(getMerkleRoot()).append("\n");
+            s.append("   witness root: ").append(getWitnessRoot()).append("\n");
             s.append("   with ").append(transactions.size()).append(" transaction(s):\n");
             for (Transaction tx : transactions) {
                 s.append(tx).append('\n');
@@ -582,11 +583,16 @@ public class Block extends Message {
     }
 
     private Sha256Hash calculateMerkleRoot() {
-        List<byte[]> tree = buildMerkleTree();
+        List<byte[]> tree = buildMerkleTree(false);
         return Sha256Hash.wrap(tree.get(tree.size() - 1));
     }
 
-    private List<byte[]> buildMerkleTree() {
+    private Sha256Hash calculateWitnessRoot() {
+        List<byte[]> tree = buildMerkleTree(true);
+        return Sha256Hash.wrap(tree.get(tree.size() - 1));
+    }
+
+    private List<byte[]> buildMerkleTree(boolean useWTxId) {
         // The Merkle root is based on a tree of hashes calculated from the transactions:
         //
         //     root
@@ -617,10 +623,15 @@ public class Block extends Message {
         //    2     3    4  4
         //  / \   / \   / \
         // t1 t2 t3 t4 t5 t5
-        ArrayList<byte[]> tree = new ArrayList<>();
+        ArrayList<byte[]> tree = new ArrayList<>(transactions.size());
         // Start by adding all the hashes of the transactions as leaves of the tree.
-        for (Transaction t : transactions) {
-            tree.add(t.getTxId().getBytes());
+        for (Transaction tx : transactions) {
+            final Sha256Hash id;
+            if (useWTxId && tx.isCoinBase())
+                id = Sha256Hash.ZERO_HASH;
+            else
+                id = useWTxId ? tx.getWTxId() : tx.getTxId();
+            tree.add(id.getBytes());
         }
         int levelOffset = 0; // Offset in the list where the currently processed level starts.
         // Step through each level, stopping when we reach the root (levelSize == 1).
@@ -749,6 +760,15 @@ public class Block extends Message {
         hash = null;
     }
 
+    /**
+     * Returns the witness root in big endian form, calculating it from transactions if necessary.
+     */
+    public Sha256Hash getWitnessRoot() {
+        if (witnessRoot == null)
+            witnessRoot = calculateWitnessRoot();
+        return witnessRoot;
+    }
+
     /** Adds a transaction to this block. The nonce and merkle root are invalid after this. */
     public void addTransaction(Transaction t) {
         addTransaction(t, true);
diff --git a/core/src/test/java/org/bitcoinj/core/BlockTest.java b/core/src/test/java/org/bitcoinj/core/BlockTest.java
index 3a2b0a32..9196647c 100644
--- a/core/src/test/java/org/bitcoinj/core/BlockTest.java
+++ b/core/src/test/java/org/bitcoinj/core/BlockTest.java
@@ -240,6 +240,14 @@ public class BlockTest {
         Block block481815 = MAINNET.getDefaultSerializer()
                 .makeBlock(ByteStreams.toByteArray(getClass().getResourceAsStream("block481815.dat")));
         assertEquals(2097, block481815.getTransactions().size());
+        assertEquals("f115afa8134171a0a686bfbe9667b60ae6fb5f6a439e0265789babc315333262",
+                block481815.getMerkleRoot().toString());
+
+        // This block has no witnesses.
+        for (Transaction tx : block481815.getTransactions())
+            assertFalse(tx.hasWitnesses());
+
+        // Nevertheless, there is a witness commitment (but no witness reserved).
         Transaction coinbase = block481815.getTransactions().get(0);
         assertEquals("919a0df2253172a55bebcb9002dbe775b8511f84955b282ca6dae826fdd94f90", coinbase.getTxId().toString());
         assertEquals("919a0df2253172a55bebcb9002dbe775b8511f84955b282ca6dae826fdd94f90",
@@ -253,6 +261,11 @@ public class BlockTest {
         Block block481829 = MAINNET.getDefaultSerializer()
                 .makeBlock(ByteStreams.toByteArray(getClass().getResourceAsStream("block481829.dat")));
         assertEquals(2020, block481829.getTransactions().size());
+        assertEquals("f06f697be2cac7af7ed8cd0b0b81eaa1a39e444c6ebd3697e35ab34461b6c58d",
+                block481829.getMerkleRoot().toString());
+        assertEquals("0a02ddb2f86a14051294f8d98dd6959dd12bf3d016ca816c3db9b32d3e24fc2d",
+                block481829.getWitnessRoot().toString());
+
         Transaction coinbase = block481829.getTransactions().get(0);
         assertEquals("9c1ab453283035800c43eb6461eb46682b81be110a0cb89ee923882a5fd9daa4", coinbase.getTxId().toString());
         assertEquals("2bbda73aa4e561e7f849703994cc5e563e4bcf103fb0f6fef5ae44c95c7b83a6",