Eighty-five venous blood specimens were collected at 4, 6 or 9 months of age from asymptomatic human immunodeficiency virus (HIV)-exposed infants and from symptomatic HIV-infected infants on admission to the hospital. The specimens were tested by in-house HIV deoxyribonucleic acid (DNA) nested polymerase chain reaction (PCR) and the commercial Amplicor HIV-1 DNA test. In order to determine the accuracy of the tests, the results were compared with the HIV infection status of the children. In-house HIV DNA PCR and the commercial Amplicor HIV-1 DNA test had overall sensitivity of 95.2 per cent and 100 per cent and an overall specificity of 100 per cent and 98.4 per cent, respectively. In the analysis of 62 HIV-exposed infants who received perinatal HIV prevention intervention, in-house HIV DNA PCR yielded 100 per cent sensitivity, specificity, positive predictive value and negative predictive value. The authors concluded that in-house HIV DNA PCR has comparable sensitivity and specificity to the Amplicor HIV-1 DNA test in detecting the HIV infection status of children born to HIV-infected mothers. The in-house HIV DNA PCR, which costs US $10 per test, should be considered in developing countries for the early diagnosis of HIV-1 infection in children.