THE LEADING CAUSE OF THE DEATH among patients with renal dysfunction is cardiovascular diseases [1], and the importance of the interaction between the heart and kidneys is widely note [2]. Plasma B-type natriuretic peptide (BNP) releases from the ventricles in response to hemodynamic stress, and BNP is one of the predictive markers for cardiovascular events [3,4].Among patients with type 2 diabetes mellitus, sev- Abstract. Among patients with type 2 diabetes mellitus, the association between B-type natriuretic peptide (BNP) and renal function remains controversial. We therefore investigated this issue among Japanese patients with type 2 diabetes mellitus. This study included 687 Japanese patients with type 2 diabetes mellitus. BNP levels were divided at quartile points on the basis of the distribution. We used four outcomes regarding the renal function: 1) chronic kidney disease (CKD): estimated glomerular filtration rate (eGFR) < 60mL/min/1.72m 2 , 2) advanced CKD: eGFR < 30mL/min/1.72m 2 , 3) microalbuminuria: urinary albumin creatinine ratio (UACR) ≥ 30 mg/g creatinine, and 4) macroalbuminuria: UACR ≥ 300 mg/g creatinine. The prevalence values of CKD, advanced CKD, microalbuminuria, and macroalbuminuria were 27.4, 2.5%, 31.4%, and 9.3%, respectively. Highest BNP (≥ 39.2 ng/mL) was independently positively associated with microalbuminuria and macroalbuminuria (adjusted ORs, 2.61 [95% CI: 1.53-4.49] and 3.45 [95% CI: 1.46-8.72], respectively). High BNP was not associated with advanced CKD or CKD. There was a statistically significant positive exposure-response relationships between the BNP level and advanced CKD, microalbuminuria, and macroalbuminuria (p for trend = 0.047, 0.001, and 0.003, respectively). BNP level may be independently positively associated with advanced CKD, microalbuminuria, and macroalbuminuria but not CKD in Japanese patients with type 2 diabetes mellitus.