Background and Objective: Ovarian tumors are among the most frequent pathologic conditions in gynecologic practice and a frequent cause of hospitalization and surgery. The aim of this study was to determine histologic distribution of benign operated masses especially functional ovarian cysts. Material and Methods: Benign ovarian files of operated patients (2961 cases) in 20 tertiary and secondary hospitals were reviewed regarding age and histopathology from 1998- 2005. Analysis was done by SPSS software (version 13). Results: The most common benign histologies in order of frequency were functional cyst (57%), serous cystadenoma (13%), dermoid cyst (10%), mucinous cystadenoma (7%) and endometrioma (6%). Conclusion: Functional cysts were the most common benign ovarian cyst. Nearly high distribution of functional cysts in the present study may be an index of need to management improvement and less surgical decisions in ovarian tumors.