The ovary is commonly involved by a wide variety of neoplasms and nonneoplastic masses. Seventy-seven ovarian masses were aspirated using fine needles. They included 29 neoplasms classified as being of celomic epithelial origin. The study was performed in order to elucidate the cytologic features of material aspirated from these neoplasms and to correlate them with the histologic features. As expected, material aspirated from malignant neoplasms was much more cellular than material obtained from benign neoplasms. By studying the background material, nuclear and cytoplasmic features of the epithelial cells, as well as the presence of other structures such as psammoma and hyaline bodies, a fairly specific pattern can be recognized for each neoplasm. Using aspiration cytology, a conclusion can be made regarding the malignant or benign nature as well as the specific type and classification of the ovarian neoplasms. Aspiration cytology, especially with the increased use of laparoscopy, has a specific role to play in the diagnosis of celomic epithelial neoplasms of the ovary. It is a valuable method when preservation of ovarian function or minimizing surgical trauma to the patient is desirable.