Background: An increased rate of hip fractures has been reported in patients with end-stage renal disease, but the effect of less severe renal dysfunction on fracture risk is uncertain. Methods: We conducted a case-cohort study within a cohort of 9704 women 65 years or older to compare baseline renal function (estimated glomerular filtration rate [eGFR] using the Cockcroft-Gault equation) in 149 women who subsequently had hip fractures and 150 women who subsequently had vertebral fractures with eGRF in 396 randomly selected women. Results: In models adjusted for age, weight, and calcaneal bone density, decreasing eGFR was associated with increased risk of hip fracture. Compared with women with an eGFR 60 mL/min per 1.73 m2 or greater, the hazard ratio (95% confidence interval [CI]) for hip fracture was 1.57 (95% CI, 0.89-2.76) in those with an eGFR 45 to 59 mL/min per 1.73 m2 and 2.32 (95% CI, 1.15-4.68) in those with an eGFR less than 45 mL/min per 1.73 m 2 (P for trend=.02). In particular, women with a reduced eGFR were at increased risk of trochanteric hip fracture (adjusted hazard ratio, 3.93 [95% CI, 1.37-11.30] in women with an eGFR 45-59 mL/min per 1.73 m2 and 7.17 [95% CI, 1.93-26.67] in women with an eGFR <45 mL/min per 1.73 m 2; P for trend=.004). Renal function was not independently associated with risk of vertebral fracture (adjusted odds ratio, 1.08 [95% CI, 0.61-1.92] in women with an eGFR 45-59 mL/min per 1.73 m2 and 1.33 [95% CI, 0.63-2.80] in women with an eGFR <45 mL/min per 1.73 m2; P for trend=.47). Conclusion: Older women with moderate renal dysfunction are at increased risk of hip fracture.