Look into a singleton patttern, that will process everything within a single thread: http://blogs.blackmarble.co.uk/blogs/msteeples/archive/2007/11/05/single-instance-biztalk-orchestrations-aka-singleton-pattern.aspx BA http://magazine.onlinetransmissions.com "Roger" <Roger@[EMAIL PROTECTED] > wrote in message news:91875C92-6F29-470C-8D6A-2C17D9E79861@[EMAIL PROTECTED] > Is there a way process one message at a time? I can receiving 1 or more > (sometimes up to 1000, but would average around 200-300 messages). But, > would > only want to process one message at a time. Because I am cauing a DLL that > uses a COM object that cannot be run at the same time.