Objective : Pathogenesis and development of human diabetic nephropathy involve in genetic factors. Since human diabetic nephropathy is a heterogeneous disorder, it is difficult to identify the responsible gene loci. Previously, we reported that the KK-A^y/Ta mouse is a suitable model for type 2 diabetic nephropathy. In the present study, we investigated the candidate gene loci for diabetic nephropathy using quantitative trait locus (QTL) analysis of KK-Ay/Ta × BALB/cA F2 intercross mice. Materials : KK-A^y/Ta and BALB/cA mice. Methods : Two hundred seventy (KK-A^y/Ta × BALB/cA) F2 intercross mice were used in this study. Urinary albumin/creatinine ratio (ACR), HbA1 c and fasting body weight were measured at 8. 12. 16 and 20 weeks of age. The genotype was investigated by 85 microsatellite markers and QTL analysis was performed. Results : ACR in mice at 20 weeks of age showed a suggestive linkage with the interval on chromosome 9 with LOD of 3.8. The gene loci that contributed to HbA1 c indicated a significant linkage to chromosome 7 (LOD 5.8, 8.9) and fasting body weight indicated a significant linkage to chromosome 1 (LOD 5.5, 5.2) in mice at 8 and 20 weeks of age. Conclusions : On QTL analysis of KK-A^y/Ta mice, several new loci contributing to diabetic nephropathy and related phenotypes were identified. It appears that type 2 diabetes and nephropathy of KK-A^y/Ta mice involve different genetic factors, but the two may act complementarily