diff --git a/include/rapidjson/document.h b/include/rapidjson/document.h
index 92c7316..ec7f8a6 100644
--- a/include/rapidjson/document.h
+++ b/include/rapidjson/document.h
@@ -662,7 +662,7 @@ public:
             return StringEqual(rhs);
 
         case kNumberType:
-            if (IsDouble() || rhs.GetDouble())
+            if (IsDouble() || rhs.IsDouble())
                 return GetDouble() == rhs.GetDouble(); // May convert one operand from integer to double.
             else
                 return data_.n.u64 == rhs.data_.n.u64;
diff --git a/test/unittest/valuetest.cpp b/test/unittest/valuetest.cpp
index 9324813..e165452 100644
--- a/test/unittest/valuetest.cpp
+++ b/test/unittest/valuetest.cpp
@@ -135,6 +135,11 @@ TEST(Value, equalto_operator) {
     TestEqual(x, y);
     TestEqual(y, z);
     TestEqual(z, x);
+
+    // Issue #129: compare Uint64
+    x.SetUint64(RAPIDJSON_UINT64_C2(0xFFFFFFFF, 0xFFFFFFF0));
+    y.SetUint64(RAPIDJSON_UINT64_C2(0xFFFFFFFF, 0xFFFFFFFF));
+    TestUnequal(x, y);
 }
 
 template <typename Value>