Pure, long‐acting gestagen, medroxyprogesterone acetate (Depo‐Provera), was tested as a contraceptive agent in a dose of 150 mg i. m. every 12th week. 139 women were observed for altogether 1 251 calendar months without any undesired pregnancy occurring in the group. The normal regular menstrual cycle was replaced initially by unpredictable vaginal bleeding and/or spotting, most often gradually followed by amenorrhoea. About 15% of the women discontinued the trial because of such menstrual irregularities. About 6% of the women stopped because of weight gain. Only few other side‐effects occurred. Withdrawal of the preparation is followed by regular ovulation and menstruation, but often not until long after the last injection. The method therefore appears to be suitable mainly for women who have decided to have no more children. The simplicity of the method, the absence of estrogen (probably involving a reduced risk of thromboembolic disease and effect on the liver), the high level of safety and reliability combined with good acceptability, despite unpredictable bleeding, and the fact that the method is well tolerated by women who had previously been unable to tolerate hormonal contraception containing estrogen, suggest that the method should have a place in our contraceptive armamentarium. However, it should not be recommended as the primary choice, at any rate not for younger women. The method is probably very suitable for women who have tried other methods without success, followed by unplanned pregnancies and subsequent legal abortions.