Androgen dependent tissue factor pathway inhibitor regulating protein (ADTRP) is a novel protein associated with coronary artery disease (CAD) susceptibility, and reduced mRNA expression of ADTRP was shown to be associated with increased CAD risk. This study aimed to determine and compare circulating ADTRP levels between CAD patients and controls, and to test the performance of plasma ADTRP as a biomarker for CAD. We measured plasma ADTRP, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high sensitivity-C reactive protein (hs-CRP) levels in 362 CAD patients, 150 angiographically negative CAD controls, and 83 healthy adults with no known clinical or medical conditions using commercial ELISA. Statistical analyses were performed using receiver operator characteristic (ROC) curves, quantile regression and logistic regression, with adjustments for age, gender, ethnicity and BMI. CAD patients had significantly lower plasma ADTRP levels 1,545 (1,087-2,408) pg/ml as compared to CAD controls 2,259 (1,533-3,778) pg/ml and healthy adults 3,904 (2,732-5,463) pg/ml. Plasma ADTRP outperformed the other three inflammatory biomarkers (TNF-α, IL-6 and hs-CRP) for CAD (Area under ROC curve: 0.67, Odds ratio (OR): 0.907). Our study has shown for the first time that ADTRP is present in circulation, and that plasma ADTRP may be a novel independent biomarker for CAD.