OBJECTIVE: To determine the frequency of adenomyosis at hysterectomies in our institution and to investigate the relationship between adenomyosis and reproductive characteristics of patients. STUDY DESIGN: We retrospectively reviewed the clinical records of all patients undergoing hysterectomy during ten years period between January 1990 and January 2000. All patients with histopathologic diagnosis of adenomyosis were determined. Patients were divided into four groups regarding to histopathologic diagnosis: adenomyosis alone (group I), adenomyosis with leiomyomas (group II), leiomyomas alone (group III) and neither (group IV). Associated pathologies, reproductive and clinical characteristics of patients were determined. We compared the reproductive characteristics of 30 patients from each group. ANOVA test and Bonferroni adjusted paired-t test were used for statistical analyses. RESULTS: Adenomyosis was diagnosed 460 of 1923 cases (23.4 %). The most common hysterectomy indication was leiomyoma (51.1 %). Leiomyoma was also found the most common synchronous pathology with adenomyosis (56.3 %). Menorrhagia was the most common complaint in patients with adenomyosis. Gravidity and abortion rates were higher in adenomyosis group (group I) than control group (group IV) (p<0.05).CONCLUSION: The frequency of adenomyosis was found high in our institution. Increased ratio of gravidity and abortion may be associated with an increased frequency of adenomyosis.