HIV infection in pediatric patients is a multisystem chronic disease that manifests as a clinical spectrum from asymptomatic infection through symptomatic infection with opportunistic infections and malignancies. The hematopoietic system is involved early in the systemic manifestations of this disease. The hematologic abnormalities seen are most probably a reflection of persistent viral infection, inflammation, and immune dysregulation, and may be complicated by secondary infections, chronic disease, drug toxicities, and nutritional deficiencies. Anemia and lymphopenia are commonly found in adult AIDS patients. Although both are also seen in pediatric patients, lymphopenia is much less common. Atypical lymphocytes with plasmacytoid characteristics have been identified in both adults and children. Pediatric bone marrow evaluation has shown an increase in plasma cells and plasmacytoid lymphocytes. Besides these findings, adult marrow findings include an increase in reticulum and lymphocytes appearing in a diffuse or aggregate pattern.