Mortality associated with hip fracture is high in elderly patients. Surgical repair within 24 hr after admission is recommended by The Royal College of Physicians' guidelines; however, the effect of operative delay on mortality remains controversial. The objective of this study was to determine whether operative delay increases mortality in elderly patients with hip fracture. Published English-language reports examining the effect of surgical delay on mortality in patients who underwent hip surgery were identified from electronic databases. The primary outcome was defined as all-cause mortality at 30 days and at one year. Effect sizes with corresponding 95% confidence intervals were calculated by using a DerSimonian-Laird randomeffects model. Sixteen prospective or retrospective observational studies (257,367 patients) on surgical timing and mortality in hip fracture patients were selected. When a cut-off of 48 hr from the time of admission was used to define operative delay, the odds ratio for 30-day mortality was 1.41 (95% CI = 1.29-1.54, P < 0.001), and that for one-year mortality was 1.32 (95% CI = 1.21-1.43, P < 0.001). In hip fracture patients, operative delay beyond 48 hr after admission may increase the odds of 30-day all-cause mortality by 41% and of one-year all-cause mortality by 32%. Potential residual confounding factors in observational studies may limit definitive conclusions. Although routine surgery within 48 hr after admission is hard to achieve in most facilities, anesthesiologists must be aware that an undue delay may be harmful to hip fracture patients, especially those at relatively low risk or those who are young.