diff --git a/changelog.md b/changelog.md
index 0ffd954b59..fbf825ca80 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,6 +1,10 @@
 Changelog
 =========
 
+## v0.6.4 - June 30, 2011
+
+Fix bug with optional callbacks for hmset.
+
 ## v0.6.2 - June 30, 2011
 
 Bugs fixed:
diff --git a/index.js b/index.js
index 2f1a067cde..33ea41042b 100644
--- a/index.js
+++ b/index.js
@@ -486,7 +486,7 @@ RedisClient.prototype.send_command = function (command, args, callback) {
             // probably the fastest way:
             //     client.command([arg1, arg2], cb);  (straight passthrough)
             //         send_command(command, [arg1, arg2], cb);
-        } else if (typeof callback === "undefined") {
+        } else if (! callback) {
             // most people find this variable argument length form more convenient, but it uses arguments, which is slower
             //     client.command(arg1, arg2, cb);   (wraps up arguments into an array)
             //       send_command(command, [arg1, arg2, cb]);
diff --git a/package.json b/package.json
index dbf42e5cb4..3ae78e7b39 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {   "name" : "redis",
-    "version" : "0.6.2",
+    "version" : "0.6.4",
     "description" : "Redis client library",
     "author": "Matt Ranney <mjr@ranney.com>",
     "contributors": [
diff --git a/test.js b/test.js
index 32e666cd3b..627f9c2123 100644
--- a/test.js
+++ b/test.js
@@ -395,6 +395,8 @@ tests.HMSET_BUFFER_AND_ARRAY = function () {
     client.HMSET(key, field1, value1, field2, value2, last(name, require_string("OK", name)));
 };
 
+// TODO - add test for HMSET.  It is special.  Test for all forms as well as optional callbacks
+
 tests.HMGET = function () {
     var key1 = "test hash 1", key2 = "test hash 2", name = "HMGET";