Kidney gene expression profile of db/db diabetic nephropathy mice was analyzed by using Affymetrix oligonucleotide genechip. Mice diabetic nephropathy related genes (and ESTs) were found out. Then, a 1.4 kb cDNA (mouse diabetic nephropathy related cDNA No.411, mdnr411, GenBank accession number AY256858) was amplified and cloned by using RACE method, based on the sequence of EST. Homologous analysis of the sequence was carried out. And the result shows that it is a new cDNA, which is highly homologous with mouse “RIKEN cDNA 5830436L09 gene (5830436L09Rik) mRNA”. The ORF of mdnr411 was predicted by using DNASIS v 2.5 Demo program. The result shows that the peptide coded by mdnr411 mRNA has 90 amino acids. And the result of homology screening did not find any obviously homologous protein, except Archaeoglobus fulgidus Na⁺/H⁺ antiporter (napA-2), which is partially homologous with the peptide coded by mdnr411 mRNA. All these results show that a cDNA of a new DNA related gene which function is fully unknown have screened and cloned. The foundation for further study of the function of the new gene, and its possible role in the pathogenesis of mice diabetic nephropathy has been laid, which is valuable to further understand the mechanism of diabetic nephropathy.