© 2016 Heart Rhythm Society Background Moderate-to-severe kidney disease increases risk for sudden cardiac death (SCD). Limited studies have evaluated how mild degrees of kidney dysfunction impact SCD risk. Objective The purpose of this study was to evaluate the association of albuminuria, which is one of the earliest biomarkers of kidney injury, and SCD. Methods The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study is a prospective, population-based cohort of U.S. adults. Associations between albuminuria, which is categorized using urinary albumin-to-creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), and SCD were assessed independently and in combination. Results After median follow-up of 6.1 years, we identified 335 SCD events. Compared to participants with ACR <15 mg/g, those with higher levels had an elevated adjusted risk of SCD (ACR 15–30 mg/g, hazard ratio [HR] 1.53, 95% confidence interval [CI] 1.11–2.11; ACR >30 mg/g, HR 1.56, 95% CI 1.17–2.11). In contrast, compared to the group with eGFR >90 mL/min/1.73 m2, the adjusted risk of SCD was significantly elevated only among those with eGFR <45 mL/min/1.73 m2 (HR 1.66, 95% CI 1.06–2.58). The subgroup with eGFR <45 mL/min/1.73 m2 (n = 1003) comprised 3.7% of REGARDS, whereas ACR 15–30 mg/g (n = 3089 [11.3%]) and ACR >30 mg/g (n = 4040 [14.8%] were far more common. In the analysis that combined ACR and eGFR categories, albuminuria consistently identified individuals with eGFR ≥60 mLmin/1.73 m2 who were at significantly increased SCD risk. Conclusion Low levels of kidney injury as measured by ACR predict an increase in SCD risk.