Introduction: Ovarian neoplasms can arise from any part of the ovary. They are not easily detected due to their location in the pelvis and presence of vague symptoms in patients. In addition, they have been known to be a cause of female infertility, morbidity, and mortality throughout the world. The ovary is the third most common site of primary malignancy in the female genital tract, preceded by cervical cancer and endometrial cancer. Aim/Objectives: This study was to determine the histopathological pattern of ovarian neoplasms at the University of Ilorin Teaching Hospital over a 20 year period (January 1990- December 2009). This was achieved by determining the total number of ovarian neoplasms seen during the period, highlighting the various histological sub types of the tumour, the age distribution and parity of the patients. Materials and Method: This was a 20 year retrospective study in which data of patients were retrieved from the histology bench register and case files of the patients diagnosed for ovarian neoplasm within the period of study. The hematoxylin and eosin (H&E) stained sections (slides) and paraffin wax blocks of the corresponding cases were retrieved and examined to confirm the diagnosis. Periodic acid Schiff (PAS) was employed in confirming the diagnosis as necessar