Background; B-type natriuretic peptide (BNP) levels can help clinicians manage patients in a great variety of settings. They are helpful in screening to identify or exclude cardiovascular disease. But, BNP level can be affect by renal function and BMI. Here, we shows impact of body mass index and renal function on the level of BNP in clinical setting. Method: A cross-sectional study about the BNP levels was conducted in 9811 patients form hospital electronic database. We obtained biochemical and clinical parameters including body mass index and serum creatinine in each patient. Results: Mean age was xxx and male was 52.2% (n=5126). The value of BNP of all subjects showed as below; mean 261.30짹 650.1, median 43.4 pg/mL. Also, the value of BNP of subjects with normal LV function, n=2460) showed as below; mean 58.08짹209.4pg/mL. Of these patients, patients with elevated serum creatinine level (��� 1.5 mg/dl, 60.0짹208.3 116.6짹232.3, p=0.020), old age (��� 70, 97.3짹230.7 vs. 46.6짹201.4 pg/mL, p=0.000), BNP level was higher. BNP levels were 167짹504 pg/mL in lean group (BMI<18.5), 32짹108 pg/mL in overweight group and 23짹36 pg/mL in obese group (BMI���30) respectively (p=0.000). The value of BNP of patients with decreased EF showed as below; mean 699짹 1075, median 240 pg/mL. The raw, and log- transformed correlations between BNP and Cr were r = 0.041, r = 0.092 and r=0.336, r = 0.277 with and without abnormal LV function. The following variables, in ranked order, were found to be most independently predictive of BNP in patient with CHF : 1) Cr, OR = 3.1, 95% CI 2.2-4.3, p =0.000 2) E/E���, OR 1.08, 95% CI 1.06-1.2, p =0.000 3) EF, OR = 0.91, 95% CI 0.89-0.93, p =0.000 4) BMI, OR = 0.89, 95% CI 0.82-0.96, p = 0.029. Conclusions: BNP may be affected from renal function and BMI regardless of LV function. Especially, in patients with abnormal LV function, adjustments for the independent effects of BMI and renal function appear necessary.