CONTEXT: Motor vehicle crash risk in older drivers is elevated in those with cataract, a condition that impairs vision and is present in half of adults aged 65 years or older. OBJECTIVE: To determine the impact of cataract surgery on the crash risk for older adults in the years following surgery, compared with that of older adults who have cataract but who elect to not have surgery. DESIGN, SETTING, AND PATIENTS: Prospective cohort study of 277 patients with cataract, aged 55 to 84 years at enrollment, who were recruited from 12 eye clinics in Alabama from October 1994 through March 1996, with 4 to 6 years of follow-up (to March 1999). MAIN OUTCOME MEASURE: Police-reported motor vehicle crash occurrence involving patients who elected to have surgery compared with those who did not. RESULTS: Comparing the cataract surgery group (n = 174) with the no surgery group (n = 103), the rate ratio for crash involvement was 0.47 (95% confidence interval, 0.23-0.94), adjusting for race and baseline visual acuity and contrast sensitivity. The absolute rate reduction associated with cataract surgery was 4.74 crashes per million miles of travel. CONCLUSIONS: In our sample, patients with cataract who underwent cataract surgery and intraocular lens implantation had half the rate of crash involvement during the follow-up period compared with cataract patients who did not undergo surgery. Cataract surgery thus may have a previously undocumented benefit for older driver safety, reducing subsequent crash rate.