The scope of the AIDS epidemic in Puerto Rico is alarming. Among states/territories and cities reporting highest numbers of AIDS cases, Puerto Rico ranks sixth in terms of the rate of cases (CDC, 1998). In Puerto Rico, as of March, 1999 (Central Office for AIDS affairs, 1999) the total number of AIDS cases is 22,903. Out of those, 138 are between the ages of 13 and 19 and 4,225 between the ages of 20 and 29. Taking into account that most people develop the AIDS virus between seven to ten years after being infected with the HIV, it is logical to assume that a great number of people are infected during their adolescent years. Any effort at preventing the spread of HIV and STDs should take place before the age of 15 which is when most adolescents are, or are close to, being sexually active. The case for primary prevention because a logical step. The first aim of this project is to develop a primary prevention program geared to reducing the risk of STDs and HIV infection in urban Puerto Rican adolescents. This program is intended to intervene with the adolescents, their parents and school personnel (teachers, social workers and other interested school personnel) of participating schools and will be developed at three different levels. The second aim to pilot test the intervention using a small quasi-experimental pre and post test with control group design. The HIV prevention intervention strategy for the students will be adapted from that developed by researchers at the University of California in San Francisco (UCSF) for high school students (Boyer, 1990). These models have been translated into Spanish and are considered to be adequate to the culture and language of Puerto Rican adolescents by the co-investigators by the co-investigator. These modules utilize a variety of communication strategies which include group exercises such as peer-facilitated, small group discussions, role playing, theater group exercises with a focus on skill building, and use of peer actors. These activities are spread over 4 sessions of about two hours each. For the parents and school personnel a four hour workshop will be developed to address the issues of the prevention of STDs and HIV infection. The third aim is to adapt a battery of assessment instruments to measure the effectiveness of the program. The proposed project will last fie years. The first year we will work on the adaptation of the instruments. The second year, we will pilot test the students intervention and develop the parents and school personnel intervention. The second year, we will pilot test the student' intervention and develop the parents and school personnel intervention. During the third and fourth year, we will administer the students' revised intervention, workshops for parents and teachers, and pre and post instruments. The fifth year will be devoted to statistical analysis, write-up and dissemination of results, feedback to parent and school personnel and students' intervention for the control group.