Mifepristone (RU 486) is a new steroid which is a progesterone antagonist and which is able to interrupt early pregnancy. The purpose of our study was to evaluate clinical efficacy and tolerance of two doses of Mifepristone (600 and 200 mg) in a single intake. The study included 205 women applying for a legal abortion with pregnancies under 7 weeks. Clinical examination was confirmed by ultrasound and plasma HCG assessment. Success was assumed by repeating these exams on 8th day. 175 patients took 600 mg of Mifepristone and 147 (84%) had a complete abortion. 30 patients took 200 mg of mifepristone and only 19 (63%) had a complete abortion. Very few side effects were observed. So, Mifepristone in able to terminate early pregnancy under medical supervision.