diff --git a/core/src/main/java/com/google/bitcoin/core/Wallet.java b/core/src/main/java/com/google/bitcoin/core/Wallet.java
index 9a92ca0126f..ea48b6c55d8 100644
--- a/core/src/main/java/com/google/bitcoin/core/Wallet.java
+++ b/core/src/main/java/com/google/bitcoin/core/Wallet.java
@@ -572,6 +572,8 @@ public int addKeys(List<ECKey> keys) {
     public int importKeys(final List<ECKey> keys) {
         lock.lock();
         try {
+            // API usage check.
+            checkNoDeterministicKeys(keys);
             int result = keychain.importKeys(keys);
             saveNow();
             return result;
@@ -580,6 +582,13 @@ public int importKeys(final List<ECKey> keys) {
         }
     }
 
+    private void checkNoDeterministicKeys(List<ECKey> keys) {
+        // Watch out for someone doing wallet.importKey(wallet.freshReceiveKey()); or equivalent: we never tested this.
+        for (ECKey key : keys)
+            if (key instanceof DeterministicKey)
+                throw new IllegalArgumentException("Cannot import HD keys back into the wallet");
+    }
+
     /** Takes a list of keys and a password, then encrypts and imports them in one step using the current keycrypter. */
     public int importKeysAndEncrypt(final List<ECKey> keys, CharSequence password) {
         lock.lock();
@@ -595,6 +604,7 @@ public int importKeysAndEncrypt(final List<ECKey> keys, CharSequence password) {
     public int importKeysAndEncrypt(final List<ECKey> keys, KeyParameter aesKey) {
         lock.lock();
         try {
+            checkNoDeterministicKeys(keys);
             return keychain.importKeysAndEncrypt(keys, aesKey);
         } finally {
             lock.unlock();
diff --git a/core/src/test/java/com/google/bitcoin/core/WalletTest.java b/core/src/test/java/com/google/bitcoin/core/WalletTest.java
index 907d72b37e0..e08653abd6f 100644
--- a/core/src/test/java/com/google/bitcoin/core/WalletTest.java
+++ b/core/src/test/java/com/google/bitcoin/core/WalletTest.java
@@ -2370,6 +2370,11 @@ public void keyRotationHD() throws Exception {
         assertNotEquals(watchKey1, watchKey2);
     }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void importOfHDKeyForbidden() throws Exception {
+        wallet.importKey(wallet.freshReceiveKey());
+    }
+
     //@Test   //- this test is slow, disable for now.
     public void fragmentedReKeying() throws Exception {
         // Send lots of small coins and check the fee is correct.