Introduction: The etiological and pathogenic factors responsible for coronary artery ectasia (CAE) are unclear. Therefore, we aimed to compare subjects with and without CAE with respect to resistin levels and determine whether resistin plays a role in the aetiology or pathogenesis of CAE.Patients and Methods: This study enrolled a total of 81 subjects, of whom 42 had CAE [15 female (F), mean age 60.4 ± 9.0 years] and 39 had a normal coronary anatomy (22 F, mean age 56.2 ± 10.7 years). Using coronary artery diameters of the control group as reference, subjects having coronary artery dilatation that was at least 1.5 times larger than the normal adjacent segments were considered to have CAE. Resistin levels were measured from blood samples obtained on the day of the coronary angiography.Results: Both the groups had similar baseline characteristics. Serum resistin levels were significantly higher in the CAE group [mean 703.5 ± 828.1 ng/L, median 379.5 ng/L] than in the control group [mean 313.5 ± 252.6 ng/L, median 256 ng/L] (p= 0.001).Conclusion: CAE and atherosclerosis share common histopathological and clinical characteristics. Resistin, a polypeptide with a known role in the development and clinical presentation of atherosclerosis, may also mediate the formation of CAE. There is a need for future studies with a larger sample size to better delineate the effect of resistin on the development of CAE.