In a recent clinical analysis of 308 Jamaican children, human T lymphotropic virus type I (HTLV-I) infection was found to be associated with significantly higher incidence rates of seborrheic dermatitis, eczema, and persistent hyperreflexia of the lower limbs and with nonsignificantly increased rates of severe anemia and abnormal lymphocytes. Results of examination of HTLV-I viral markers in the 28 HTLV-I-infected children provided virologic support for the epidemiologic associations of HTLV-I with seborrheic dermatitis and severe anemia in childhood.