diff --git a/src/js/ripple/serializedtypes.js b/src/js/ripple/serializedtypes.js
index 663d6649..094d3c87 100644
--- a/src/js/ripple/serializedtypes.js
+++ b/src/js/ripple/serializedtypes.js
@@ -562,7 +562,7 @@ STPathSet.id = 18;
 
 var STVector256 = exports.Vector256 = new SerializedType({
   serialize: function (so, val) { //Assume val is an array of STHash256 objects.
-    var length_as_varint = SerializedType.serialize_varint(so, val.length);
+    var length_as_varint = SerializedType.serialize_varint(so, val.length * 32);
     for (var i=0, l=val.length; i<l; i++) {
       STHash256.serialize(so, val[i]);
     }
diff --git a/test/serializedtypes-test.js b/test/serializedtypes-test.js
index 126c0d38..1944a933 100644
--- a/test/serializedtypes-test.js
+++ b/test/serializedtypes-test.js
@@ -807,6 +807,12 @@ describe('Serialized types', function() {
         "RootIndex": "000360186E008422E06B72D5B275E29EE3BE9D87A370F424E0E7BF613C465909"
       }
       assert.deepEqual(as_json, expected_json);
+      assert.throws(function () {
+        // This is an encoded reminder/TODO:
+        // Serializing ledger entries isn't currently supported, but when it
+        // is, this should no longer throw, and the test will fail
+        assert.strictEqual(SerializedObject.from_json(expected_json).to_hex(), hex);
+      })
     });
     it('Serialize empty object {}', function () {
       var so = new SerializedObject();