Limit of antiretroviral treatment success is the emergence of drug-resistant virus. As reported in adult population, prevalence of resistance was high in treated HIV-infected children with detectable HIV viral load. Resistance increased with number of prior antiretroviral treatments, particularly with protease inhibitors. Adolescent boys seem at greater risk to harbor multi-classes resistant virus. In HIV-infected newborns, prevalence of resistance was 20%. Most of resistance mutations detected were in accord to perinatal antiretroviral exposition. Principal mechanism of resistance acquisition in newborns was transmission of resistant viruses from mother to child with early archive in cellular reservoir and long term persistence with or without treatment. Consequences of long term therapeutic strategies in children are major.