Abstract： Objective To study the relationship between the mutant in insulin receptor (INSR) gene and type 2 diabetes. Methods INSR-tyrosine kinase(IRTK) domain gene (exon 17-21 of INSR gene) in 107 patients with type 2 diabetes were examined by PCR-SSCP, and the abnormal exons were then sequenced. Results 13 nonsense mutants in exon 17 and 1 mutant in exon 20 were found. Mutant exon 20 was a sense mutation at position 1191 (GAC→AAC,Asp →Asn). Conclusion In patients with type 2 diabetes, the frequency of sense mutations in IRTK gene is relatively low. The Asp 1191→Asn mutant may result in the abnormal conformation of INSR, and more work is needed to study on the effect of this aberrance.