I am working on a db where an alphanumeric number field must advance by one number with each new record. This must also be unique, no duplicates. Example: Z000001, Z000002, Z000003 etc. The other kicker is the Numbers will be assigned in groups of numbers to a specific district (13 different districts). Example 1 district will be assigned numbers of: Z000001 to Z005000, another district will be assigned Z005001 to Z010000 etc. None of the 13 districts may have duplicate numbers. This is a government program for official documents, they will assign the alphanumeric numbers ("Certificate Numbers") I'm not an expert on access so your help would be appreciated. Thanks, Randy