Introduction: Impaired coronary endothelial function (CEF) is a known predictor of cardiovascular (CV) events and occurs in people living with HIV. HIV+ women compared to men have worse CV outcomes, but prior studies include very few women. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is related to endothelial cell inflammation and is elevated in HIV+ men. CEF and PCSK9 are not well studied in women with HIV. Hypothesis: We hypothesize that HIV+ women have worse CEF and higher PCSK9 levels compared to risk factor matched HIV- women, and that CEF will be associated with PCSK9 in HIV+ women, similar to prior findings in HIV+ men. Methods: A total of 34 HIV+ women and 75 HIV+ men on stable highly active antiretroviral therapy and 17 HIV- women and 8 HIV- men underwent MRI to measure CEF (%change in coronary artery cross-sectional area (%CSA) and coronary blood flow (CBF) during isometric handgrip exercise, an endothelial dependent stressor). Serum PCSK9 samples were obtained on the day of MRI. Comparisons were performed using student’s t-test for normally distributed and Kruskal-Wallis test for data not normally distributed. Robust regression was used for the association of PCSK9 with CEF. Results: CEF was significantly reduced in HIV+ women compared to age-, race- and BMI-matched HIV- women (p<0.001 for both %CSA and %CBF change Fig. 1A-B). Both HIV+ men and women had similarly impaired CEF. Women with HIV had significantly higher PCSK9 levels than women without HIV (Figure 1C). Further, PCSK9 was significantly inversely associated with %CSA (ß -0.03(-0.06,0.00); p=0.038) in men but not in women (ß -0.02(-0.04,0.01); p=0.26). Conclusions: Coronary endothelial dysfunction is present among HIV+ women as compared to risk factor matched HIV- women. HIV+ women have similarly depressed CEF as HIV+ men. With HIV, PCSK9 is not significantly associated with CEF, suggesting potential alternative mechanisms of impaired CEF in men and women with HIV.