AN 8-YEAR-OLD BOY with human immunodeficiency virus (HIV) was seen for routine evaluation. At the time of HIV diagnosis (age 4½ years), his CD4 cell count was 17 cells/µL (reference range, >1000 cells/µL), and findings from neurologic examination were normal. Treatment was started with zidovudine, trimethoprim sulfate, rifabutin, and monthly intravenous immunoglobulin, but the CD4 cell count remained low. At age 6½ years, he had been performing poorly in school. Findings from neurologic examination showed 2 to 3 beats of ankle clonus bilaterally. A magnetic resonance imaging study (MRI) had been obtained. The patient later developed anemia, leukopenia, elevated creatine phosphokinase levels, and elevated lactic dehydrogenase levels, all of which resolved when zidovudine was discontinued. At age 7 years, he was hospitalized for persistent fever with no source found. Nephrotic syndrome was diagnosed based on renal biopsy findings showing minimal changes of the disease, and he had intermittent hypertension; both resolved by age 8½ years after treatment with didanosine, stavudine, and ritonavir. CD4 cell counts improved to 646 cells/µL.