: Integrase strand transfer inhibitor-based antiretroviral therapy can cause weight gain. It is unknown if this is a class effect, with limited data regarding raltegravir. In 37 virologically suppressed adults (36 men, mean age 49 years) who switched from tenofovir disoproxil fumarate to raltegravir 400 mg twice daily, mean weight changes from baseline at weeks 24, 48 and 96 were not significant (maximum 0.8 kg at week 24; all P ≥ 0.16). Weight gain may not occur with all integrase strand transfer inhibitors.