Objectives: To evaluate effectiveness of Anti-Retroviral Therapy (ART) services on clinical outcomes and survival of HIV infected children [0-15 years) in Swaziland. Study design: A retrospective cohort analysis of medical records for 4170 HIV-infected children who were initiated on ART between 2004 and 2008 was conducted. The Signed-ranks test, Kaplan Meier Estimator, and Cox-P H regression model were used to compare clinical outcomes between relevant predictors. Results: The results reveal that clinical outcomes for HIV-infected children on ART were desirable as indicated by significant CD4 gain (from 17 CD4% to 35 CD4%, 14 CD4% to 34 CD4%, and from 194 to 592 CD4 count in mm3 for children aged [0-2) years, [2-5) years and [5-15) years, respectively, p<=0.001). Early initiated children were dying at a rate estimated to be 67% times lower than children who were delayed ART (p-value<=0.001). Children within the age group of [2-5) years had higher hazard (HR=1.59, 95% CI: 1.33-1.89) of death than children within the age group of [5-15) years. Conclusions: The ART paediatric programme in Swaziland proved to be effective as demonstrated by positive clinical outcomes. Early initiation proved to be effective in increasing survival time for children.