Abstract Objective To investigate the possible role of apolipoprotein M (ApoM) in the development of coronary artery disease (CAD). Design and methods Case-controlled study, which consisted of 118 CAD patients and 255 unrelated subjects used as control group. Plasma concentration of ApoM was determined by dot blot, severity of CAD was expressed with Gensini score or the numbers of lesioned coronary arteries, and serum lipid levels were also measured. Results and discussion Our study shows the mean level of plasma ApoM is 1.3757 ± 0.1493 ODu mm − 2 in CAD patients, while it is 1.3502 ± 0.1288 ODu mm − 2 in control group, and there are significant differences in plasma level of ApoM between two groups ( t = 0.032, P < 0.05). Concentration of plasma ApoM is positively associated with plasma total cholesterol ( r = 0.38, P = 0.025), high density lipoprotein cholesterol ( r = 0.29, P = 0.03), low density lipoprotein cholesterol ( r = 0.16, P = 0.03) and apolipoproein A–I ( r = 0.24, P = 0.03). Multiple logistic and linear regression analysis showed that plasma concentration of ApoM did not correlate either with the number of lesioned coronaries or the Gensini score after adjusted for conventional cardiovascular risk factors ( P > 0.05, respectively). Conclusion The findings suggest that ApoM could not be an independent risk factor but a biomarker of CAD.