Background: Coronary artery disease (CAD) is the most common type of heart disease and causes high morbidity worldwide. The β3-adrenergic receptor gene (ADRB3) is potentially linked to obesity, insulin resistance, diabetes, and hypertension based on its role in energy homeostasis and lipolysis in human adipose tissue. However, the relationship between ADRB3 gene polymorphisms and CAD remains unclear. we sought to assess this association in the Han and Uygur populations of China. Methods: We used the following two case-control studies: a Han population (308 CAD patients and 294 control subjects) and an Uygur population (259 CAD patients and 161 control subjects). All 1022 participants were genotyped for the two single nucleotide polymorphisms (SNPs) (rs1892818, rs9693898) of ADRB3 using real-time polymerase chain reaction (TaqMan). Results: We found that the rs1892818 CT genotype (8.5% compared with 3.9%, P = 0.019) and T allele (4.3% compared with 1.9%, P = 0.021) were more frequent in control subjects than in CAD patients of the Han, but not Uygur population. No significant differences in rs9693898 of ADRB3 were found between CAD patients and control subjects for both populations. After adjusting for other confounders, logistic regression analysis suggested that the difference remained significant between the two groups in the Han population (CT compared with CC, P = 0.036, OR = 0.410, 95% CI: 0.178–0.944). Conclusion: Our results suggest that ADRB3 rs1892818 is associated with CAD in a Han population and that the CT genotype of ADRB3 rs1892818 might be a protective factor for CAD in Han individuals.