Depot medroxyprogesterone acetate (DMPA) has been available for several decades in many parts of the world including Thailand, but few data have been reported concerning adolescents. The aim of the study was to determine the use of DMPA for contraceptive use among Thai adolescents. A cross-sectional study has been designed. A total of 108 adolescents who used DMPA as contraception between January 1, 1996, and December 31, 1997, at King Chulalongkorn Hospital were reviewed by chart. Most of the participants were in late adolescence and average age was 17.6 years of age. Six-month continuation rate was 69.4%, and at 9 months and 1 year were 42.6 and 30.6%, respectively. Irregular bleeding, amenorrhea, and weight gain were the side effects frequently reported. The most common side effect that caused discontinuation within 1 year was irregular bleeding. With prolonged use, the number of cases with irregular bleeding decreased and the duration of bleeding was shortened, whereas the rate of amenorrhea increased. No pregnancy occurred during the study period. In conclusion, DMPA is an effective contraception in adolescents. However, the continuation rate is lower than that for adult women. The main reason for discontinuation is irregular bleeding.