HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome)has emerged as the single most formidable challenge to public health, human rights and development in the new millennium. This is an interventional study carried out during November from the academic school year 2006-2007 and aimed to assess AIDS-related knowledge, attitudes and misconceptions among female secondary school students within their social context at Gharian city in Libyan Arab Jamahiriya and to determine the effect of health education on changing them. Subjects of the study included 465 female secondary school students, selected through a multistage stratified random sample from female secondary schools at Gharian city situated in the western part of Libya. The tool used for assessment was confidentially administered closed ended questionnaire both before and after the education programme of 45 minutes single class, standardized education package). The results of this study revealed that Television and Radio were the main source of information (92.9%), followed by "newspapers and magazines"(39.1%, then books( 23.2%) and teachers(16.1%). Parents (11.2%) and friends (7.9%) represented the lowest source of information about HIV/AIDS among students. Also, this study revealed that the percentage of correct answers about knowledge of HIV/AIDS and the causative agent of the disease were significantly improved after health education regarding all items from a range of 67.1% to 79.1% pre education to a range of 89.2% to 97.8% post education. A significant positive correlation was found between knowledge of HIV/AIDS and each of the following : age of the students (r=0.6231,P