To assess the role of information sources and socio-demographic factors on knowledge about AIDS in female adolescents.Cross-sectional survey.Three different girls colleges of Lahore. Study was conducted from September 1999 to November 1999.The sample of 600 students was divided into various colleges according to the total strength of students in the college. The students filled a semi structured questionnaire anonymously. To assess the overall knowledge of students a scale with a range of 0-49 score was developed for 49 items inquired to assess knowledge about AIDS. On the basis of this score students were divided into satisfactory and unsatisfactory knowledge groups by using the 50th percentile as the cut off point.Eighty percent of those students whose mothers and 58% of those students whose fathers had postgraduate qualifications had satisfactory knowledge of AIDS as compared to those students whose parents were graduate and undergraduate (p <0.0001). Similarly, significantly higher knowledge of AIDS (p <0.0001) was observed in those students whose mothers were working as compared to those students whose mothers were housewives, as well as those whose parents' monthly income exceeded Rs 10,000. Those students who read the editorial, columns and magazine section of newspapers had satisfactory knowledge about AIDS as compared to those students who read the political and sports section of the newspapers. Access to television, satellite channels and Internet had a statistically significant effect on knowledge about AIDS (p<0.0001). Significant higher knowledge of AIDS was observed among those students who discussed AIDS with their sisters and friends (p <0.05) as compared to those students who discussed AIDS with their parents and teachers.Those students who belonged to higher socioeconomic group and had educated parents had satisfactory knowledge about AIDS. The newspaper and electronic media also have an important role in transmitting knowledge about AIDS. Family members, friends and teachers can prove to be a potential source for dissemination of information about AIDS.