A low dose of oral contraceptive, containing 0.5 mg norgestrel and 0.05 mg ethinyl estradiol, was given daily tc 303 women for a total of 5,159 cycles in order to study its efficacy and acceptability as an oral contraceptive agent. Only one pregnancy occurred. The cycle length was markedly stabilized, and the duration of bleeding was shortened and 88.5% of the treated cycles were 3 to 5 davs. Breadthrough bleeding and amenorrhea occurred rarely during the cycles under medication. Main side effects observed were gastro‐intestinal symptoms and weight gain. The gastro‐intestinal symptoms were more frequent in the first 3 cycles, but gradually decreased in later cycles, showing good tolerance of the drug, while the weight gain occurred in 4.2% of 303 women. In the liver function tests employed, abnormalities in BSP retention, serum transaminase values or TTT were recorded in a limited number of cases. However, neither jaundice nor thrombophlebitis was observed in any cases treated, while hypertension occurred in 4 cases. The drug investigated can be evaluated as acceptable to most women seeking contracept