One hundred fifty seven females of childbearing age, suffering from diabetes mellitus, were examined. A severe form of the disease was revealed in 55% of the patients and in 59% of the females its duration did not exceed 5 years. Previous unfavourable obstetric findings were seen in 73.6% of the patients. A disturbed menstrual cycle was found in 33% of patients. In the females with a preserved menstrual cycle the blood estradiol content was significantly reduced in all cyclic phases, and in amenorrhea it was low (50 +/- 8.4 pg/ml). The degree of clinical signs of the ovarian function disorder is directly dependent on the severity of diabetes mellitus.