Aim: To assess the effect of cashew nut flour on the hematological parameters of children living with HIV-AIDS. Method: A 32-week randomized, blind clinical trial conducted at a specialized outpatient clinic. Children aged 2–12 years were allocated to intervention groups (IGs) (n = 11) receiving 12 g/day of cashew nut flour and control groups (CGs) (n = 9) receiving 12 g/day of carboxymethyl cellulose. Parameters of erythrocytes, leukocytes, platelets, and lipid profiles were evaluated. Results: In the IG, the elevation and reduction of leukocyte and lipid profile biomarkers, respectively, were not statistically significant (p > 0.05). A clinically and statistically significant increase in mean corpuscular hemoglobin concentration was observed in the CG (p = 0.018), with a large effect size (Cohen's d = 0.9). There were no statistically significant changes in platelet counts among participants (p = 0.18). The effect size for white blood cell count, low-density lipoprotein cholesterol, very low-density lipoprotein, and triglycerides was moderate in the IG compared to the CG. Conclusion: Cashew nut flour supplementation may increase levels of leukocytes and lipid profile parameters in children living with HIV. Brazilian Clinical Trials Registry (REBEC): U1111.1276.6591.