Objectives To study the relationships between methylenetetrahydrofolate reductase(MTHFR ) gene polymorphism and diabetic retinopathy (DR) in Chinese Han race． Methods With polymerase chain reaction and restriction fragment length polymorphism (PCR-FLP), MTHFR gene 677 T mutation (cytosine is replaced by thymine in No. 677 site) was detected in 85 health controls, 62 with DR and 117 without DR of type 2 diabetics comfrimed by ophthalmoscope． Results The frequency of MTHFR variant genotypes and alleles of DR in Chinese Han race．patients were signigicantly higher than those without retinopathy and healthy controls (Plt;0．01)． Conclusions The results suggested that MTHFRgene C677T mutation was probably one of the genetic risk factors of diabetic retinopathy in Chinese Han rase． (Chin J Ocul Fundus Dis, 2001,17:198-200