BACKGROUND: Previous studies demonstrated that,metabolic phenotype of cytochrome P450 2C19 has genetic polymorphism,which presents with extensive or poor metabolisms and has great differences in races and individuals.OBJECTIVE: To study the genotype distribution of cytochrome P450 2C19 in Xinjiang Uigur population.METHODS: In total 144 unrelated Uigur and 156 unrelated Han subjects were genotyped for cytochrome P450 2C19 by polymerase chain reaction-restriction fragment length polymorphism.The differences of gene phenotype and gene frequency were compared between Uigur and Han populations.RESULTS AND CONCLUSION: The frequency of extensive metabolism wt/wt,wt/m and wt/m1+wt/m2 of Uigur was notably higher than that of Han population(P<0.05),but the frequency of poor metabolism m1/m1 was obviously lower than that of Han population(P<0.05).There were significant differences between Uigur and Han populations in allele frequency wt,m1 and m2(P<0.05),especially m1,which was 58-fold of m2(P<0.01).The results revealed that,distribution frequency m1/m1 of poor metabolism of Uigur is obviously lower than that in Han population,and m1 frequency is higher than that of Han population,accordingly,m1 is the main gene mutation of cytochrome P450 2C19 in Uigur population.