Objectives: To evaluate potential sex differences and other factors associated with complications within 4 months after a hip fracture. Methods: A total of 1,915 patients. 65 years (480 men) with hip fracture were consecutively included in a prospective multicenter cohort study. A review of medical records and patient interviews according to a study protocol based on the Standardized Audit of Hip Fractures in Europe (SAHFE, RIKSHOFT) was performed. Sex differences in comorbidity according to the American Society of Anesthesiologists score and complications 4 months after a hip fracture were registered. Multivariate logistic regression analysis was performed to identify factors related to complications. Results: Male sex was associated with worse general health according to the American Society of Anesthesiologists classification (P=0.005) and with more comorbidities (P<0.001). Male sex emerged as a risk factor for developing pneumonia (P<0.001), and additionally, 18% of the men suffered from cardiac complications compared with 13% of the females (P=0.018). Female sex was predisposed for urinary tract infections, 30% vs 23% in males (P=0.001). Mortality was higher in the male vs female group, both within 30 days (15% vs 10%, P=0.001) and at 4 months (24% vs 14%, P=0.001). Conditions associated with pneumonia were male sex, pulmonary disease, and cognitive impairment. Cardiac complications were associated with delayed surgery and cardiovascular and pulmonary disease. Conclusion: Before surgery, men with hip fracture already have a poorer health status and higher comorbidity rate than women, thus resulting in a twofold increased risk of pneumonia. Cognitive dysfunction and pulmonary disease contributed to pneumonia in men. Delayed surgery seems to increase the risk for cardiac complications. It is important to consider the sex perspective early on together with cardiopulmonary comorbidity and cognitive dysfunction to be able to counteract serious complications that may lead to death.