Answer
The number of allowable fields for any feature class or table in a geodatabase depends on the limitations of the database in which the geodatabase is stored. While file geodatabases have a limit of 655346 fields per table, the limit for personal geodatabases is governed by the .mdb file format, which has a limit of 255 fields per table. Therefore, personal geodatabases stored in an Access database may have a feature class or table with no more than 255 fields. The answer for feature classes or tables stored in an ArcSDE Geodatabase varies depending on the underlying DBMS.