Inflammation plays a pivotal role in the pathogenesis of chronic kidney disease (CKD). Significant association between serum albumin-to-globulin (AG) ratio and inflammation led us to investigate the prognostic value of serum AG ratio for incident CKD. The predictive value of serum AG ratio, white blood cell (WBC), and C-reactive protein (CRP) for CKD development was assessed in 8,057 non-CKD participants from a community-based, prospective cohort in Korea. Serum AG ratio was calculated by following equation: serum albumin (g/L)/[serum total protein (g/L)-serum albumin (g/L)]. Incident CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m2 and/or proteinuria of more than 1+ on dipstick. Median serum AG ratio was 1.38 (interquartile range, 1.28-1.52). During a mean follow-up duration of 9.1±3.7 years, 1,732 participants (21.5%) developed CKD. In a multivariable Cox analysis, a low serum AG ratio was significantly associated with an increased risk of incident CKD (Q1, serum AG ratio <1.26: hazard ratio [HR]=1.651, 95% confidence interval [CI]=1.406-1.938, Q5 as reference; per 1 standard deviation decrease, HR=1.170, 95% CI=1.109-1.234). Serum AG ratio was the only indicator to improve the predictability of CKD development (net reclassification index=0.158, P <0.001; integrated discrimination improvement=0.005, P <0.001), compared with WBC or CRP. This study demonstrates that low serum AG ratio is an independent predictor for CKD development and exhibits a stronger predictive value than other inflammatory markers. These findings suggest that determining serum AG ratio may be more valuable for predicting adverse kidney outcomes in non-CKD populations.