diff --git a/include/zmq.h b/include/zmq.h
index 4754c6ff..d610d195 100644
--- a/include/zmq.h
+++ b/include/zmq.h
@@ -205,7 +205,10 @@ ZMQ_EXPORT int zmq_ctx_destroy (void *context);
 /*  0MQ message definition.                                                   */
 /******************************************************************************/
 
-typedef struct zmq_msg_t {unsigned char _ [64];} zmq_msg_t;
+/* union here ensures correct alignment on architectures that require it, e.g.
+ * SPARC and ARM
+ */
+typedef union zmq_msg_t { unsigned char _ [64]; void *p; } zmq_msg_t;
 
 typedef void (zmq_free_fn) (void *data, void *hint);