Objective: Because human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) may occur in some children infected with HTLV-1, we sought to determine the prevalence of neurologic abnormalities and any associations of neurologic abnormalities with infective dermatitis in these children. Study design: We enrolled 58 children infected with HTLV-1 and 42 uninfected children (ages 3 to 17) of mothers infected with HTLV-1 in a family study in Lima, Peru. We obtained medical and developmental histories, surveyed current neurologic symptoms, and conducted a standardized neurologic examination without prior knowledge of HTLV-1 status. Results: HTLV-1 infection was associated with reported symptoms of lower extremity weakness/fatigue (odds ratio [OR], 6.1; confidence interval [CI], 0.7 to 281), lumbar pain (OR, 1.7; 95% CI, 0.4 to 8), and paresthesia/dysesthesia (OR, 2.6; CI, 0.6 to 15.8). HTLV-1 infection was associated with lower-extremity hyperreflexia (OR, 3.1; CI, 0.8 to 14.2), ankle clonus (OR, 5.0; CI, 1.0 to 48.3), and extensor plantar reflex (OR undefined; P = .2). Among children infected with HTLV-1, a history of infective dermatitis was associated with weakness (OR, 2.7; CI, 0.3 to 33), lumbar pain (OR, 1.3; CI, 0.2 to 8), paresthesia/dysesthesia (OR, 2.9; CI, 0.5 to 20), and urinary disturbances (OR, 5.7; CI, 0.5 to 290). Conclusions: Abnormal neurologic findings were common in Peruvian children infected with HTLV-1, and several findings were co-prevalent with infective dermatitis. Pediatricians should monitor children infected with HTLV-1 for neurologic abnormalities. © 2009 Mosby, Inc. All rights reserved.