The clinical and pathological features of 25 serous papillary cysta-denomas of borderline malignancy of the broad ligament were analyzed. The ages of the patients ranged from 19 to 67 (average, 32) years. The clinical presentation was lower abdominal pain, pelvic pain or both in five cases, accompanied by menometrorrhagia or amenorrhea in three cases. One patient was thought to have an acute abdominal disorder. The tumors of the remaining 19 patients were discovered either on routine gynecological examination or during an evaluation of the pregnancy status of the patient. In 14 cases the tumor was located in the left broad ligament and in 11 cases it was on the right side; all the tumors were entirely separated from the ipsilateral ovary. On gross examination the tumors were 1–13 cm in greatest dimension, had smooth outer surfaces, and contained straw-colored, watery fluid. The inner lining bore single or multiple 0.3–2.5 cm excrescences. Microscopic examination revealed that the cyst walls and their excrescences were lined by simple to pseudo-stratified, cuboidal to columnar, focally ciliated epithelium. Slight nuclear atypism, very rare mitotic activity, and focal psammoma body formation were also found. The stroma resembled ovarian stroma but no primary follicles or follicular derivatives were identified. Twenty-three of the patients were alive and well from 0.5 to 11 years after excision of the tumor, one patient was disease-free for 8.5 years but died of an open-heart surgical procedure; and two patients were lost to follow-up examination.