The contraceptive effect of Depo-Provera or medroxyprogesterone acetate, a long-acting injectable progestogen, has been mainly attributed to its ability to prevent ovulation through its action on the hypothalamic pituitary axis, reducing the levels of plasma gonadotropin, progesterone, and estradiol, and suppressing the midcycle surge of luteinizing hormone. Its other contraceptive effects are thickening of the cervical mucus, causing a barrier to spermatozoa, alteration in tubal ovum transport, and atrophy of the endometrium. A standard dose of 150 mg injected every 3 months is as effective as the combined oral pill and more effective than the progestogen-only pill or IUD. Contraindications to use are thrombophlebitis, liver dysfunctions, suspected breast or genital malignancy, and abnormal uterine bleeding. Reported discontinuation rates range from 7-80%. The World Health Organization (1977) reported a gross cumulative discontinuation rate of 23.4/100 women years in 8 centers. Depo-Provera has a long list of short-term (menstrual disorders, fluid retention, nausea, hair loss, and others) and long-term (delayed fertility return, congenital abnormalities, cancer others) disorders. Its advantages include: 1) convenience, 2) effectiveness, 3) no risk of infection or other side effects of the coil, 4) none of proven side effects or long-term hazards of estrogen, and 5) no inhibition of lactation. The safety of Depo-Provera has been a controversial issue which led to its banning in the U.S. Its carcinogenic potential has been reported in clinical trials with animals. Its greatest disadvantage is that it takes control of a woman's fertility firmly out of her hands into those of the doctor. Depo-Provera should not be used except as an absolute last resort. It should not be used as a long-term contraceptive in this country, and research monies should instead be channeled into the development of a safe, reliable contraceptive with no systemic side effects.