Objective Total knee arthroplasty (TKA) is a widely utilized and effective treatment option for end-stage knee osteoarthritis (OA). Knee OA is more prevalent among women compared to men, but there are limited data on the sex differences in surgical outcomes after primary TKA. Methods Our sample consisted of all primary TKAs performed in Pennsylvania during the fiscal year 2002. We used International Classification of Diseases, Ninth Revision, Clinical Modification codes to identify major complications and surgical revision. We used mixed-effects logistic regression models to examine the associations between sex and all-cause mortality, readmissions, and major surgical complications. We used proportional hazards models to assess the risk of surgical revision after index arthroplasty. We adjusted for race, age, hospital teaching status, hospital procedure volume, insurance status, and risk of mortality. Results In 17,994 primary TKAs, there were 46 and 220 deaths at 30 days and 1 year, respectively. Compared to women, men had higher adjusted odds of 1-year mortality (odds ratio [OR] 1.48 [95% confidence interval (95% CI) 1.13-1.94]) after primary TKA. The overall odds of most major 30-day complications did not differ by sex except for surgical wound infections, which were higher in men compared to women (OR 1.31 [95% CI 1.08-1.60]); 30-day readmission was higher in men (OR 1.25 [95% CI 1.10-1.43]). Men had significantly higher rates of revision of index knee arthroplasty at 5 years (hazard ratio 1.20 [95% CI 1.05-1.36]) compared to women. Conclusion The higher rates of mortality, hospital readmissions, revision surgery, and wound infections in men undergoing elective primary TKA compared to women indicate there is a sex disparity in these outcomes. Copyright © 2013 by the American College of Rheumatology.