OBJECTIVE: Our purpose was to evaluate the efficacy and safety of depot medroxyprogesterone acetate versus an oral contraceptive combined with very-low-dose danazol in the long-term treatment of pelvic pain in women with endometriosis. STUDY DESIGN: Eighty patients with endometriosis and moderate or severe pelvic pain were randomized to treatment for 1 year with intramuscular depot medroxyprogesterone acetate 150 mg every 3 months or a cyclic monophasic oral contraceptive (ethinyl estradiol 0.02 mg, desogestrel 0.15 mg) combined with oral danazol 50 mg a day for 21 days of each 28-day cycle. The women were asked to grade the degree of their satisfaction at the end of therapy. Variations in severity of symptoms during treatment were determined by a 10 cm visual analog and a 0- to 3-point verbal rating scale. RESULTS: Twenty nine of 40 subjects (72.5%) in the depot medroxyprogesterone acetate group were satisfied after 1 year of therapy compared with 23 of 40 (57.5%) in the oral contraceptive plus danazol group (χ 2 1 = 1.37, p = 0.24, odds ratio 1.95, 95% confidence interval 0.76 to 4.97). A significant decrease was observed in all symptom scores in both study groups. At 1-year assessment dysmenorrhea was significantly greater in women allocated to oral contraceptive plus danazol. CONCLUSION: Depot medroxyprogesterone acetate seems to be an effective, safe, and convenient low-cost treatment for pelvic pain associated with endometriosis. However, women should be carefully counseled regarding menstrual changes and the potential prolonged delay in the return of ovulation. (Am J Obstet Gynecol 1996;175:396-401.)