Angiogenesis and arteriogenesis have a crucial role in the formation of coronary collateral vessels. It has been shown that endocan and vascular cell adhesion molecule-1 (VCAM- 1) are potential angiogenetic factors. We investigated the relationship between serum endocan levels and grade of coronary collaterals, and also the correlation of endocan levels with serum VCAM-1 levels. Patients with stable angina and at least one total coronary occlusion at invasive coronary angiography were included in our study. Collateral degree was graded according to Rentrop and Cohen's classification. Patients who had grade 0 or 1 collateral vessels were included in the poorly- developed collateral group, and those with grade 2 or 3 coronary collateral vessels were included in the well- developed collateral group. Serum endocan and VCAM-1 levels were significantly higher in the well- developed collateral group (436.6 +/- 213.3 ng/ mL vs. 216.1 +/- 78.5 ng/ mL, p<. 001; 11.02 +/- 6.58 ng/ mL vs. 6.78 +/- 1.14 ng/ mL, p<. 001, respectively). In a logistic regression analysis, only serum endocan level remained as an independent predictor for good collateral development. In the ROC curve analysis, 282 ng/ mL endocan level had an a 82% sensitivity and 86% specificity for prediction of the well- developed collateral group. Higher endocan level was related to better coronary collateral development. In the event that these results are confirmed in further studies, endocan may be considered as an anti- ischemic treatment strategy in order to improve collateral development.