The goal of study was to evaluate the efficacy of LOW-DOSE DESOGESTREL in reducing endometriosis associated pain compare to standard therapy of DIENOGEST. Objects and methods. There were 63 women in fertile age with chronic pelvic pain syndrome, associated with small peritoneal and uterine form of endometriosis. They were randomized for 2 groups. The 36 women in first group had been taken desogestrel 0,075g for 6 months; the 27 women in second group were treated by dienogest 0,02g during the same period of time. There were 23 women (13 in first group and 10 in second one) with laparoscopycally confirmed endometriosis. Background for diagnosis in the others cases was anamnesis, pelvic examination, ultrasound and MRI. Patients with ovarian endometriomas and nodal forms of endometriosis were excluded. The intensity of the pain syndrome was assessed by the VAS before treatment, 3 and 6 months after. Results. Two patient from the fist group and three from the second group were prematurely excluded from the study because of side effects. Severity of pain syndrome was the same in both groups before treatment. Pelvic pains during the menstrual periods were estimated as 7,8±1,4 and 7,6±1,3 VAS in the first and second groups respectively; deep dyspareunia as 7,6±1,3 and 7,4±1,4 VAS; pain during the gynecological examination - 7,9±1,1 and 8,0 ±1,2 VAS. After 3 months of treatment severities of all types of pain were less in the both groups. The pelvic pain were estimated as 2,6 ±0,6 and 2,4 ±0,7 VAS in the first and second groups respectively, deep dyspareunia as 3,2 ± 1,1 and 4,3 ± 1,3 VAS, pain during the gynecological examination 5,61± 1,3 and 5,0 ± 1,4 VAS. There wasn’t significant difference between two groups. After 6 months of treatment the reducing of the pain severity was the same and consist of 1,9± 0,4 and 2,0 ± 0,6 VAS for pelvic pain, 2,8 ± 0,7 and 2,6 ± 0,6 VAS for deep dyspareunia in the first and second groups. The endometrial thickness, measured by the ultrasound examination, was the same and shown as the thin line. Big follicles were noticed more often in the first group. The side effects were different in the desogestrel and dienogest groups. The bleeding and spotting were more often in the first group; headache and skin complications were more likely in the second group. Conclusion. The reducing of the small endometriosis associated pain has the same efficacy for desogestrel and dienogest. Cost-effect ratio was better for desogestrel.