Did you search prior to make the question?...usually if you search you may find something.

There is no such Zip code for Qatar.

Here it is used the PO BOX system.

Anyway and if you need additional details there have been several posts on this topic on previous dates.

http://www.qatarliving.com/search?cx=008937172676595728955%3A066rihafv68...

Regards!!!