This paper examines the determinants of sexual behaviour with special reference to the effect of household socio-economic status as a proxy for poverty. The data are derived from the Nigeria Demographic and Health Survey; the analysis is restricted to 1,831 never married females age 15-24. Both descriptive and analytical methods are used to assess the effects of each poverty-related factor when the effects of other demographic and socio-cultural factors are controlled statistically. The results show that 31.5% of the respondents have had sexual intercourse, and more than half of these had an affair in the month preceding the survey. The median age of sexual debut is 17 years, and there is little variation among socio-demographic and poverty-related indices, indicating a generally early initiation of sexual activity. Condom use is low among the youth; only 15% have ever used condom, and about 22% of the sexually experienced used condom the last time they had an affair. The results indicate that those who have access to the media and those of high socio-economic status are more sexually exposed than their counterparts who do not have access to media or have less household facilities. Exposure to premarital sex increases with access to newspapers, radio and television. The data do not support the view that the high level of sexual activity is a function of household poverty, although poverty exposes the youth to reproductive health risks as a result of low usage of condom among those from less well-off homes.