Adipocyte fatty acid binding protein-4 (A-FABP4) and retinol binding protein-4 (RBP4) have recently been linked to type 2 diabetes mellitus (DM). Serum A-FABP4 and RBP4 levels and their relationships with early diabetic nephropathy were examined in 87 type 2 diabetic patients. The patients with diabetic nephropathy showed high A-FABP4 levels compared to the patients without diabetic nephropathy (p = 0.0001). Log A-FABP4 correlated positively with age (p = 0.02), log duration of diabetes (p = 0.04), log body mass index (BMI) (p = 0.0001), log creatinine (p = 0.007), log C-reactive protein (CRP) (p = 0.01), log albumin excretion rate (AER) (p = 0.001), and negatively with MDRD-GFR (p = 0.0001). Serum RBP4 levels were similar between the patients with and without diabetic nephropathy. RBP4 correlated positively with triglycerides (p = 0.001), log creatinine (p = 0.009), and negatively with MDRD-GFR (p = 0.04). In regression analysis, log A-FABP4 was associated with age, sex, log BMI, and log AER (r(2) = 0.43) and RBP4 was associated with triglycerides and log creatinine (r(2) = 0.22). In conclusion, we found high serum A-FABP4 but unchanged RBP4 concentrations and their associations with renal function and early diabetic nephropathy in type 2 DM. (C) 2010 Elsevier Ireland Ltd. All rights reserved.