15(S)15-methyl PGF2alpha methyl ester was self-administered vaginally to terminate pregnancy in 42 women in the 8-9th week of gestation. Ten patients received a total of 6 mg of the compound over 15 hours (Group I) while the remaining 32 patients received 5.5 mg of the prostaglandin compound during a shorter period of time or 9 hours (Group II). If parts of the conceptus were expelled during treatment, surgical intervention was excluded. All patients were followed closely after treatment with repeated serum HCG assays and clinical examinations. All patients in Group II and eight out of ten patients in Group I aborted following treatment. In 33 of the 42 patients, the serum HCG levels and the clinical course following the expulsion of the conceptus indicated that abortion was complete. Gastro-intestinal side effects were minimal if anti-diarrheic agents were given prophylactically. The incidence of uterine pain was variable but could in most cases be controlled by oral or rectal administration of analgetics. The results of this study suggest that the use of this compound for termination of pregnancy may be safely extended through the 9th week of gestation and in certain cases be an alternative to the normal operative procedure.