© 2016 Elsevier Inc. Background It is unknown if higher levels of ambient particulate matter (PM) exposure increase the risk for premature ventricular contractions (PVC) in a population-based study of men and women, and if this relationship varies by race or sex. Methods We examined the association of PM <2.5 µm in diameter (PM2.5) concentration with PVCs in 26,121 (mean age=64±9.3 years; 55% female; 41% black) participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Estimates of short- (2-week) and long-term (1-year) PM2.5exposures were computed prior to the baseline visit using geographic information system data on the individual level at the coordinates of study participants’ residences. PVCs were identified from baseline electrocardiograms. Results PVCs were detected in 1719 (6.6%) study participants. Short- (OR=1.08, 95%CI=1.03, 1.14) and long- (OR=1.06, 95%CI=1.01, 1.12) term PM2.5exposures were associated with PVCs. Interactions were not detected by race or sex. An interaction between short-term PM2.5exposure and PVCs was detected for those with cardiovascular disease (OR=1.16, 95%CI=1.06, 1.27) compared with those without cardiovascular disease (OR=1.05, 95%CI=0.99, 1.12; p-interaction=0.027). Conclusion Our findings suggest that PM2.5exposure is associated with an increased risk for PVCs in a biracial population-based study of men and women. We also have identified persons with cardiovascular disease as an at-risk population for PVCs when increases in short-term PM2.5concentration occur.