Aim: Genetic polymorphisms causing Ser49Gly and Gly389Arg mutants of β1-adrenoceptor may result in significant changes in the function of this receptor.The aim of the present study was to investigate the frequencies of the Ser49Gly and Gly389Arg mutant alleles in healthy Chinese populations and to investigate the differences between 2 Chinese ethnic groups (Han and Dai populations) with respect to the frequencies of these alleles. Methods: A total of 225 Han Chinese and 175 Dai Chinese unrelated healthy volunteers were recruited for this study.Genomic DNA was extracted from peripheral blood leukocytes by using a standard manual chloroform-phenol extraction. Fragments spanning the 2 polymorphisms were amplified by using polymerase chain reaction with template genomic DNA and relevant primers. The DNA products including the polymorphic loci were subjected to restriction endonuclease digestion with Eco0l09I and BcgI.Digested fragments were detected with an ultraviolet detector after electrophoresis (100 V for approximately 1.5 h). Results: The frequencies of the Gly49 and Arg389 alleles were, respectively, 16.2% and 76.4% in the Han population and 14.6%and 75.7% in the Dai population. Conclusion: The polymorphisms causing the Ser49Gly and Gly389Arg mutations of the β1-adrenoceptor existed in both healthy Han and Dai Chinese populations. The frequencies of the Ser49Gly and Gly389Arg mutant alleles were not significantly different in the Han and Dai populations.However, the frequency of the Gly389 variant seems to be significantly lower in these 2 populations than in an African-American population.