This study is a retrospective chart review to determine the association of Charlson Comorbidity Index (CCI), age, body mass index (BMI), and admission glucose with the incidence of postoperative 30-day mortality in older patients undergoing hip fracture surgery from January 1, 2000, to June 30, 2002. A total of 40 (8%) of 485 eligible patients died within 30 days after hip fracture surgery. The factors associated with 30-day mortality were age > 90 years (odds ratio [OR] = 2.74; confidence interval [CI] = 1.27-5.95; P = .012), BMI < 18.5 (OR = 3.98; CI 1.48-10.65; P = .006), and CCI ≥ 6 (OR = 2.6; CI = 1.20-5.65; P = .015). There was no relationship between admission glucose concentration and 30-day mortality. Advanced age, low BMI, and high CCI can be identified prospectively and are independently associated with postoperative 30-day mortality in older, chronically ill patients.