Human immunodeficiency virus infection in children has a different way of presentation. The involvement of muscular system is most commonly described as pyomyositis because of opportunistic infections or myopathy secondary to highly active antiretroviral therapy in both children and adults. Primary myopathy presenting as a progressive weakness is usually seen in adults and rarely observed in children with only a few cases described in the literature. In this case, we report a 7-year-old Indian girl with perinatal HIV infection presenting with progressive weakness and otherwise asymptomatic. An improvement was observed after antiretroviral and rehabilitative therapy.