A fertility survey of unmarried adolescents and young adults (953 males and 829 females) in Greater Accra and Eastern regions of Ghana revealed that a substantial proportion of the respondents were sexually experienced. Overall, 66·8% of the males and 78·4% of the females were sexually experienced. The mean ages (±SD) of the males and females were 15·5±2·5 and 16·2±2·0 years, respectively. Most respondents claimed to have received adequate information on reproductive health and sexually transmitted diseases (STDs), including AIDS. However, 20% and 30% of the respondents in peri-urban and rural areas, respectively, did not know that a girl could get pregnant the first time she has sexual intercourse. The incidence of pregnancy among the unmarried female respondents was relatively high (37%), and was higher in urban than in rural areas. Approximately 47% of those who had ever been pregnant reported that they had had an abortion. Levels of contraceptive awareness were high (98·2% among males and 95·5% among females) but many still engaged in unprotected sexual relations. The most commonly used methods were the condom and the pill. The main reasons given for non-use were that they did not think about contraception, were concerned about the safety of contraceptives, and partner objection. These findings point to the need for targeting of unmarried adolescents and young adults with information on reproductive health and family planning to increase their awareness of the risks of pregnancy, STDs and HIV infection.