RESUMEN
AIDS is an infectious and very dangerous disease that in spite of many attempts to find effective drugs and treatments is still a global health problem. It seems that in addition to medical efforts, social matters and personal hygiene play a big role in controlling this disease. To evaluate knowledge and attitude of high school students [boys and girls] about AIDS. A descriptive, cross-sectional study was performed. Using cluster random sampling, 22 districts of Tehran were divided to five areas according to their geographic position and in each area, two districts were selected and in each district, two boy and girl high schools were selected. Finally, from each high school, 40-45 students in grade 1, 2 and 3 were selected through simple random sampling, and information was gathered from 5000 students by interviewers using questionnaires. Data showed that students' knowledge about AIDS was moderate and their attitude was negative, especially in boys. There was a direct, significant correlation between amount of knowledge and attitude, with higher knowledge leading to more positive attitude. Student s knowledge was also increased by increasing level of education. Given the direct association between knowledge and attitude and the importance of preventive behaviors, improvement of students' knowledge is of great importance. This can be achieved by building committees in different provinces across the country and by public education of all the students