The prevalence of hepatitis A virus (HAV) protective antibody in 98 Thai HIV-infected children who achieved immune recovery after antiretroviral therapy was 12.2%. After a 2-dose HAV vaccination, 98.8% (85 of 86 children) seroconverted. The geometric mean titer was 520.95 mIU/mL. In a multivariate analysis, female gender, age < 12 years and higher CD4 lymphocyte count at enrollment were predicting factors for high (≥ 250 mIU/mL) HAV antibody response.