IMPORTANCE Critical access hospitals are a predominant source of care for many rural populations. Previous reports suggest these centers provide lower quality of care for common medical admissions. Little is known about the outcomes and costs of patients admitted for surgical procedures. OBJECTIVE To compare the surgical outcomes and associated Medicare payments at critical access hospitals vs non-critical access hospitals. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional retrospective review of 1 631 904 Medicare beneficiary admissions to critical access hospitals (n = 828) and non-critical access hospitals (n = 3676) for 1 of 4 common types of surgical procedures-appendectomy, 3467 for critical access and 151 867 for non-critical access; cholecystectomy, 10 556 for critical access and 573 435 for non-critical access; colectomy, 10 198 for critical access and 577 680 for non-critical access; hernia repair, 4291 for critical access and 300 410 for non-critical access-between 2009 and 2013. We compared risk-adjusted outcomes using a multivariable logistical regression that adjusted for patient factors (age, sex, race, Elixhauser comorbidities), admission type (elective, urgent, emergency), and type of operation. EXPOSURES Undergoing surgical procedures at critical access vs non-critical access hospitals. MAIN OUTCOMES AND MEASURES Thirty-day mortality, postoperative serious complications (eg, myocardial infarction, pneumonia, or acute renal failure and a length of stay >75th percentile). Hospital costs were assessed using price-standardized Medicare payments during hospitalization. RESULTS Patients (mean age, 76.5 years; 56.2% women) undergoing surgery at critical access hospitals were less likely to have chronic medical problems, and they had lower rates of heart failure (7.7% vs 10.7%, P < .0001), diabetes (20.2% vs 21.7%, P < .001), obesity (6.5% vs 10.6%, P < .001), or multiple comorbid diseases (% of patients with Ն2 comorbidities; 60.4% vs 70.2%, P < .001). After adjustment for patient factors, critical access and non-critical access hospitals had no statistically significant differences in 30-day mortality rates (5.4% vs 5.6%; adjusted odds ratio [OR], 0.96; 95% confidence interval [CI], 0.89-1.03; P = .28). However, critical access vs non-critical access hospitals had significantly lower rates of serious complications (6.4% vs 13.9%; OR, 0.35; 95% CI, 0.