This is a pilot study to determine the safety, toxicity, virologic and immunologic effects of combination therapy with hydroxyurea, a cytostatic chemotherapeutic agent, two nucleoside reverse transcriptase inhibitors and a non-nucleoside reverse transcriptase inhibitor in children with HIV infection. We will enroll HIV-infected children who have detectable viral loads (greater than 10,000 copies/ml). Patients will be stratified upon enrollment by CD4 cell count (less than or greater than 200 CD4 cells/mm(3)). Two dose levels of hydroxyurea will be utilized (7.5 mg/kg/dose twice daily and 12.5 mg/kg/dose twice daily). It is anticipated that 15 patients will be enrolled at the Low Dose Level and 10 patients at the High Dose Level of hydroxyurea within each CD4 cohort, for a total of 50 patients on study. Within each dose level patients will receive the antiretroviral agents didanosine, stavudine and efavirenz beginning on study Day one and will be randomized to receive hydroxyurea either on Day 1 or week 6. The cohorts will be escalated and analyzed separately. The study duration will be 52 weeks. This study will attempt to define an effective and tolerable dose of hydroxyurea.