The AIDS Program at the University of Puerto Rico Children's Hospital (UPR- UCH) is the leading center for treatment and research for children with AIDS in Puerto Rico. UPR-UCH involvement in AIDS clinical trials began in 1988 with support from NICHD (IVIG Clinical Trial Study Group). Following the merger of NICHD funded sites with the NIAID funded Pediatric ACTU's, UPR-UCH enrolled children into ACTG available pediatric protocols. Investigators from UPR-UCH (Clemente Diaz, M.D., Carmen Zorrilla, M.D.) have participated as members of the ACTG Pediatric Core Committee and the Women's Core Committee. In addition, scientific contributions to the ACTG have included development of a phase I tolerance and toxicity study of Alpha-interpheron alone and in combination with Zidovudine (Protocol 153) in children with early disease progression. Other major research interests include HIV-related malignancies; opportunistic infection prophylaxis; measurement of compliance with anti- retrovirals; neurodevelopmental problems; and quality of life indicators in children with HIV. Strong ties with community support organizations and comprehensiveness of health care services, has allowed a remarkable long-term retention rate of children enrolled in protocols. This is evidenced by the 31 month adherence to study visit schedule rate in the IVIG Clinical Trial and the 18 month rate of WITS. In WITS, this rate is the highest both for accrual and retention of all participating centers.