: Heightened systemic inflammation contributes to cardiovascular (CVD) events in people living with HIV (PLWH), although not all PLWH develop CVD, thus suggesting a genetic modifying role. We examined GCH1 polymorphisms, which have been associated with reduced endothelial function in European populations with CVD and increased inflammation, in a racially diverse cohort of US PLWH initiating antiretroviral therapy (ART). GCH1 polymorphisms differed by race and were not associated with flow-mediated dilation or carotid intima-media thickness before or after 48 weeks of ART.