To examine sex differences in inpatient mortality and 30-day and 90-day readmissions after coronary artery bypass grafting (CABG) among a multistate population. A retrospective analysis of patient hospitalization and discharge records. All-payer patients in nonpsychiatric hospitals in New York, Maryland, Florida, Kentucky, and California. A total of 304,080 patients from the State Inpatient Databases Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality from January 2007 to December 2014 who underwent CABG surgery. Bivariate analysis and multivariate logistic regression were performed to obtain unadjusted rates and adjusted odds ratios, respectively, for in-hospital mortality and readmissions by sex. Of the patients who underwent CABG, 5,699 patients (1.87%) died, including 2,131 women (2.65%) and 3,568 men (1.60%). The authors found that women were 32% more likely to die compared with men (adjusted odds ratio [aOR]: 1.32, 95% confidence interval [CI]: 1.25-1.40) after adjusting for age, race, insurance status, median income, Elixhauser comorbidity index measures, year of procedure, state, and hospital surgical volume. Women, compared with men, also had significantly increased adjusted odds of 30-day and 90-day readmissions (30-day aOR: 1.24, 95% CI: 1.21-1.28; 90-day aOR: 1.25, 95% CI: 1.22-1.28). This study demonstrated that female patients who undergo CABG are at a greater risk of in-hospital death and 30-day and 90-day readmission compared with men. This sex-based disparity in outcomes has persisted since identification some 40 years ago.