The survival experience of pediatric AIDS patients from three points: birth, age at first symptom and age at AIDS diagnosis (by the WHO definition) was studied. We had 90 subjects, 46 males and 44 females. They were under 15 years of age and were diagnosed as having perinatally-acquired pediatric AIDS. The children came to Srinagarind Hospital between January, 1989 and December, 1997. They were followed-up until April 30, 1998. Patients who did not come to the hospital were traced by confidential mail. The two most common first symptoms were chronic diarrhea (36.7%) and persistent lower respiratory tract infection (34.4%). The median age at the first symptom was four months (95% CI = 3 to 5 months) and the median age at diagnosis was 13 months (95% CI = 11 to 15 months). Thirty-nine cases received antiretroviral treatment, either AZT, ddI or both. Forty-five cases died, 18 cases lived to the end of the study, 27 could not be followed-up. A survival curve was calculated according to the Kaplan and Meier method using SPSS version 6.0. The 1- and 2-year survival rates from the time of the first symptom were 75.3 per cent (95% CI = 65.8% to 84.7%) and 60.3 per cent (95% CI = 49.0% to 71.6%). The corresponding survival rates from AIDS diagnosis were 59.7 per cent (95% CI = 48.4% to 71.1%) and 42.8% (95% CI = 30.3% to 55.3%), respectively.