Rates of emergency contraception (EC) use in sub-Saharan Africa are highest in Kenya and Nigeria, although little is understood about user characteristics and use dynamics in these countries. In order to better meet the emergency contraceptive needs of women, and contribute to the limited knowledge base on EC in Africa, this study examines a large, representative sample of EC users. It draws on data collected from household surveys that included 7,785 sexually experienced women in urban Kenya and 12,653 sexually experienced women in urban Nigeria. Bivariate and multivariate analyses found that among these urban women, knowledge of EC was higher than reported in other nationally representative surveys (58% in Kenya and 31% in Nigeria). About 12% of sexually-experienced women in Kenya and 6% in Nigeria ever used EC, although fewer women (less than 5%) reported using EC in the past one year. Recent users of EC were more likely to be in their twenties, unmarried, and more highly educated than never users or ever users of EC in both countries. Results contradict public perceptions of EC users as younger adolescents, and indicate the importance of strengthening EC provision in Africa, including targeting information and services to unmarried women and supporting private pharmacies in delivering quality EC services.