Premarital sex is associated with the phenomenon of teenage and unintended pregnancies, abortion, the spread of STIs and HIV. The major objective of this study was the investigation of premarital sexual activities in an urban society of South-west Nigeria. The aim is to quantify premarital sexual behaviour in the study population. Interview method was used to collect information from a sample of 2,500 women within the age bracket of 15-49 years. Percentage distribution and logistic regression were used in the analysis. The results reveal a very high rate of sexual activities; 14.24% had had sex before age 14, and 84% had sex before their 20 th birthday at which age only 1.28% of the sample had married. Premarital sexual activities are highly associated with age, age at marriage and puberty. The study calls for the empowerment of the younger population especially girl child through sexual right education to avoid the negative consequences associated with premarital sex.