This study was conducted between 1994 and 2004 in cross-section in 4000 women hospitalized in some Iranian hospitals for fibroadenoma. In the study the following factors were examined: age, menstrual cycle pattern, age of menarche, menopause after 50 years, oral contraceptive use, mastalgia, marriage, number of full-term pregnancies, first pregnancy over age 35 years, history of breastfeeding, cigar smoking, the kind of radiology for diagnosis, the place of tumor, tumor location in breast, diameter of tumor, multiple tumor, patient background and family history of fibroadenoma, and pathology report.