PIP: Norethisterone oenanthate (NET-OEN), an injectable contraceptive preparation containing 200 mg of steroid in 1 ml oily solution, was administered to 126 healthy Thai women of proven fertility (age, 18 to 35) at 8-week and then 12-week intervals. Vaginal bleeding, weight, blood pressure and menstrual bleeding were recorded during each visit, as were complaints and adverse effect. The 12-month continuation rate was 63/100 women-years with 5 accidental pregnancies. There were 2 pregnancies during the 2nd injection interval and 3 other pregnancies during the 3rd, 4th, and 5th injection intervals. Most frequent complaints were spotting, 32.4% and amenorrhea, 26.2%. 3.8% experienced heavy bleeding while 11.2% reported vertigo, nausea and vomiting. There were 11/100 women-years of amenorrhea, and 25/100 women-years of heavy bleeding. A statistically significant increase in the serum glucose tolerance test (p 0.05) was noted after 12 months of use, but the increase was within normal limits. The significant transient decrease in total cholesterol and triglyceride levels observed at the 3rd month of study returned to normal after 6 months.