Higher serum cystatin C level is associated with an increased risk of hip fracture in postmenopausal white women, but there is a paucity of data for men. Whether estimated glomerular filtration rate (eGFR) based on cystatin C (eGFR cys ) is superior in predicting hip fracture risk to eGFR based on creatinine (eGFR cr ) or the combination (eGFR cr-cys ) also is uncertain.Nested case-cohort.Participants enrolled in the Osteoporotic Fractures in Men (MrOS) Study (5,994 men aged ≥65 years from 6 US centers) including a random subcohort of 1,602 men and 168 men with incident hip fractures (51 of whom were in the subcohort).eGFR cys , eGFR cr , and eGFR cr-cys computed using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations and expressed in categories of <60, 60-74, and ≥75 mL/min/1.73 m 2 (referent group).Incident hip fracture ascertained by participant contacts every 4 months and confirmed with radiographic reports.Median eGFR cys was 72.9 (IQR, 60.5-85.7) mL/min/1.73 m 2 . In unadjusted models, all measures of eGFR were associated with increased hip fracture risk. However, after adjustment for age, race, site, and body mass index, the association of lower eGFR cys (but not lower eGFR cr or lower eGFR cr-cys ) with higher hip fracture risk remained: for <60 versus ≥75 mL/min/1.73 m 2 , HRs were 1.96 [95% CI, 1.25-3.09], 0.84 [95% CI, 0.52-1.37], and 1.08 [95% CI, 0.66-1.77] for eGFR cys , eGFR cr , and eGFR cr-cys , respectively. Similarly, after adjustment for age, race, site, and body mass index, eGFR < 60 mL/min/1.73 m 2 defined by eGFR cys , but not eGFR cr or eGFR cr-cys , was associated with higher hip fracture risk. The association between eGFR cys and hip fracture was not explained by levels of calciotropic hormones or inflammatory markers, but the relationship was attenuated and no longer reached significance (for <60 vs ≥75 mL/min/1.73 m 2 : HR, 1.43; 95% CI, 0.88-2.34) after consideration of additional clinical risk factors and bone mineral density.Findings not generalizable to other populations; residual confounding may exist.Older community-dwelling men with lower eGFR cys have an increased risk of hip fracture that is explained in large part by greater burden of risk factors among men with lower eGFR cys . In contrast, lower eGFR cr or lower eGFR cr-cys was not associated with a higher age-adjusted hip fracture risk.