An elevated serum anion gap is known to be associated with hypertension, low cardiorespiratory fitness, and decreased renal function. We evaluated whether serum AG might be predictive of elderly mortality in a community-based cohort in Korea. We analyzed the available data from 862 elderly people in the Korean Longitudinal Study on Health and Aging. Over a 5-year observational period, 151/862 (17.5%) participants died, and a high albumin-adjusted anion gap (SAAG) was associated with an increased risk of all-cause mortality in unadjusted analyses (hazard ratio [HR], 1.96; 95% confidence interval [CI], 1.41-2.71) and fully adjusted analyses (HR, 1.77; 95% CI, 1.24-2.52), compared with a low SAAG group. The population attributable fraction of death due to high SAAG was 38.2% (95% CI 20.7-58.2%). In particular, the participants with high SAAG had higher cardiovascular and infection-related mortality rates than those with low SAAG (HR, 2.11; 95% CI, 1.06-4.19, and HR, 9.69; 95% CI, 1.12-83.4, respectively). High SAAG may be an independent predictor of mortality and is associated with higher cardiovascular and infection related mortality in the elderly.