Ovarian cysts are detected in female patients of all ages. The patient's age, the size of the cyst, and the ultrasound appearance are helpful in determining which ovarian cysts necessitate observation and which necessitate surgical excision. The cancer antigen 125 level alone does not help to distinguish between benign and malignant ovarian cysts. The combination of benign findings on pelvic examination, a benign ultrasound appearance, and a cancer antigen 125 level within normal limits indicates a benign origin in practically all cases.