BACKGROUND: Nigeria accounts for about 10% of all HIV/AIDS cases in the world. Globally women constitute 48% of adults infected with HIV; in Nigeria, they constitute 57%. There is an increase in the number of children infected with HIV in recent years as the number of HIV-positive women has increased. However, more than 90% of HIV infections in children aged less than 15 years are due to mother-to-child transmission of HIV. OBJECTIVE: To evaluate the awareness and knowledge of mother-to-child transmission of HIV, HIV/AIDS and the methods to prevent mother-to-child transmission of HIV. METHODS: This is a descriptive study. The study was carried out at the pediatric HIV clinic of Aminu Kano Teaching Hospital from 1 st July 2006 to 30 th December 2006. Mothers included in the study were mothers in first contact with HIV facilities, which was at our center, before any form of counseling. The instrument used was a questionnaire designed to assess awareness of the mothers about HIV/AIDS, evaluate their knowledge of possible routes of transmission and measures to prevent vertical transmission. The questionnaire was then pre-tested for comprehensibility, appropriateness of language, sensitivity of questions and average duration of administration. RESULTS: A total of 164 mothers brought their children for treatment to the pediatric HIV clinic. The level of awareness about HIV/AIDS among mothers was very high (100%), and the main sources of information were radio (48.8%) and television (37.8%). Ninety-one percent of mothers were aware of mother-to-child transmission of HIV. Transplacental route (41%) was the commonly identified route of transmission. The level of knowledge and perceptions of mother-to-child transmission of HIV is inadequate. CONCLUSION: There is a need to scale up education about mother-to-child transmission of HIV in our health facilities.