The rapid development of ultrasound technology and its routine application during gynecological examinations has led to the more frequent detection of ovarian cysts. Such cysts can be diagnosed at any age or stage of a woman's life, and detected as early as the fetal stage or as late as the postmenopause. Ovarian cysts in female fetuses are usually detected during screening in pregnancy and followed after delivery as neonates. A few months are usually sufficient for spontaneous regression, although symptomatic cysts should be promptly operated. In fertile women, most cases present benign functional cysts which disappear after menstruation or can be managed easily with the combined oral contraceptive pill. When pregnancy is complicated with an adnexal mass, the second trimester is the preferable time of action in cases when operation is demanded. Transvaginal sonography plays an important role, not only in the detection of ovarian cysts but also in the diagnosis of malignancy. Large cysts, multiloculi, septa, papillae and increased blood flow are all suspected signs of neoplasia. The incidence of ovarian cancer increases with age and is predominantly a disease of peri- and postmenopausal women with an average patient age of 50-59 years. Vaginal sonography has been established as the examination of choice in screening and follow-up of patients, with complementary color Doppler studies and determination of serial serum levels of CA-125. If a malignant cyst is suspected, at any age, explorative laparotomy should be performed promptly. Sonographic or computerized tomographic scanner aspiration procedures, as well as laparoscopic surgery, should be reserved for diagnostic or therapeutic purposes in low-risk cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)