The role that host genetics plays in the modification of the rate of human immunodeficiency virus 1 (HIV-1)-related disease progression was evaluated in a seroprevalent cohort of 1049 children with symptomatic HIV-1 infection who participated in 2 clinical trials in the United States. Variants including CCR2-V64I, CCR5-wt/Delta32, CCR5-59029-G/A, CCR5-59353-T/C, CCR5-59356-C/T, and SDF1-3'-G/A were identified by polymerase chain-reaction genotyping. Children with the CCR5-wt/Delta32 genotype experienced significantly delayed disease progression, including less neurocognitive impairment. In the CCR5-wt/wt group, the most rapid disease progression was in those with the CCR5-59029-A/A genotype, which was present in 23% of the children. Although the SDF1-3'-A/A variant was associated with more-rapid disease progression, it occurred in <2% of the children studied. Modest or little impact was associated with the CCR5-59353, CCR5-59356, or CCR2 genotypes. Thus, in children with the CCR5-wt/wt genotype, variants at CCR5-59029 have the broadest impact on disease progression. These data suggest that, in children, host genetics plays an important role in HIV-1-related disease progression and neurological impairment.