Introduction: Peripheral artery disease (PAD) is associated with decreased physical function and increased mortality in the general population. PAD is common in women with and at risk for HIV infection, but its association with functional decline is unclear. We examined the contribution of PAD to gait speed in the Women’s Interagency HIV Study, controlling for traditional cardiovascular risk factors and HIV-related factors. Methods: 1,839 participants (72% HIV+) with measured ankle-brachial index (ABI) and 4-meter gait speed were included in analysis. ABI scores were categorized as: <0.7, moderate-severe PAD; 0.7-<0.9, mild PAD; 0.9-<1.0, borderline PAD; 1.0-<1.1, low-normal; 1.1-1.4, normal. Longitudinal regression models with repeated measures were used to examine the association of PAD category with log-transformed gait speed after controlling for demographic, behavioral, and cardiovascular disease risk factors, and HIV and HCV status. Coefficients represented percentage differences. Results: Median age was 50 years, >70% were Black. Figure 1 shows median gait speed by PAD group. In univariate analysis, compared to normal ABI, each category of PAD severity was associated with slower gait speed: 6% slower for low-normal (95% confidence interval [CI]:4%, 9%), 10% for borderline (95% CI:6%, 13%), 14% for mild (95% CI:9%, 18%), and 16% for moderate-severe (95% CI:5%, 25%). In multivariate analysis, PAD severity remained associated with 6% (95% CI:4%, 9%), 10% (95%CI:7%, 14%), 12% (95%CI:8%, 17%), and 11% (95%CI: -1%, 22%) slower gait speed, respectively. HIV/HCV coinfection reduced gait speed by 9% (95%CI:4%, 14%). Among HIV+ women, neither CD4 count nor HIV viral load was associated with gait speed. Conclusions: In middle-aged women with and at risk for HIV, greater PAD severity is associated with progressively slower gait speed. ABI measurement may be a simple and clinically useful tool for early assessment of functional declines.