Aim To investigate whether antihypertensive efficacy in patients with hyprtension was impacted by polymorphism and methylation of β1-adrenoreceptor (β1-AR) gene. Methods Three hundred hypertensive patients enrolled began taking metoprolol by the same dose;the genotype of their β1-AR gene by PCR-RFLP was tested to compare the antihypertensive efficacy among patients with different genotype.The methylation state in β1-AR gene detected by methylation specific PCR(MSP) from peripheral blood of patients with the same genotype was controlled by the subjects with normal blood pressure,to make a inquiry into the relationship between the modification and the antihypertensive response to metoprolol. Results Patients with Arg389Arg genotype got significant greater decrease in diastolic blood pressure as compared with Gly389Arg and Gly389Gly(8.0%±1.3% vs 4.0%±1.5% and 3.0%±1.1%,P<0.05);and the β1-AR gene from peripheral blood of all subjects was methylated. Conclusions Polymorphism at Gly389Arg of β1-AR gene was associated with antihypertensive response to metoprolol;the methylated modification on β1-AR gene from human peripheral blood was not found to be related to the response.