M.A. Umar , O.E. Olowofeso , R.A. Ademiluyi , Modeling Horizontal Transmission of HIV/AIDS in an Age-Structured Population, Journal of Modern Mathematics and Statistics, Volume 2,Issue 6, 2008, Pages 174-180, ISSN 1994-5388, jmmstat.2008.174.180, (https://makhillpublications.co/view-article.php?doi=jmmstat.2008.174.180) Abstract: We extended McKendrick-Von-Foerster type age-structured model to formulate a 2-age groups structured for heterosexual transmission of HIV/AIDS, in a proportionate mixing population, with constant per capital force of infection. We derive the governing equations, which describes the dynamics of population and examine the model for local stability of the endemic state. We found that to get a disease-free state we need to maximize the transfer rate between the sexually immature group and sexually matured group and minimize the average time spend as infective in group 2, before developing AIDS. Keywords: Transmission;HIV/AIDS;population;modeling;age-structured;mixing population;Nigeria