BACKGROUND: HIV and unintended pregnancy are major interrelated concerns in sub-Saharan Africa. Focussing on single women aged 15-24 years we assess trends in key behaviours that affect both outcomes. METHODS: We performed a secondary analysis of public-access data sets from 112 surveys from 36 countries in the region, conducted between 1991 and 2015. We examined trends over 20 years in primary abstinence (virginity), secondary abstinence (no sex in past 3 months) among sexually experienced women, current use of modern contraception and condom use at most recent coitus among sexually active women. RESULTS: Little change occurred in primary or secondary abstinence. Over the 20 year period, contraceptive use in the region rose from 14.7 to 33.4%, with significant increases observed in 18 of 30 countries with multiple surveys. Since 2001-2005, the proportion of contraceptive users reporting condoms as their method fell from 61.1 to 51.3%, while use of oral contraceptives or injectables rose from 19.9 to 24.0%. Between 1996 and 2000 and 2006-2010, condom use at last coitus rose from 21.3 to 40.5% but then plateaued. A strong correlation between condom use and national HIV prevalence was found. About half of condom users at last sex had earlier in interviews reported this method for pregnancy-prevention. CONCLUSIONS: Though condoms tend to be overlooked by both HIV and family planning agencies, their contribution to the health of single women remains central. Current efforts to promote non-barrier contraceptive methods may inadvertently increase HIV risk. Condom promotion for pregnancy-prevention should be re-invigorated by social marketing campaigns and other means.