The long-term postoperative occlusion of venous or arterial grafts following coronary artery bypass graft surgery (CABG) is a constant and unresolved problem, with a negative impact on clinical outcome. In our study, we aimed to find predictors that influence graft patency. The data of 202 patients who underwent CABG and had control coronary angiography on an average of 8.55 ± 4.56 years were analyzed retrospectively. Based on the presence of graft occlusion ascertained at control coronary angiography, patients were divided into two groups: 81 in the graft occlusion group (with 89 grafts degeneration: 64 saphenous vein [SVG] and 25 arterial graft) and 121 in the control group with patent grafts. The two groups were considerably well-matched regarding patient characteristics. Among medical conditions, peripheral artery disease has been found to be an independent predictor of increased graft occlusion, but only in SVG patients (OR 3.64, CI 1.21-11.03, p = 0.021). When evaluating medical therapy, significantly more patients were on nebivolol in the control group, compared to the graft occlusion group (p = 0.032). Moreover, nebivolol has been found to be an independent predictor of a lower degree of graft occlusion development (OR 0.36, CI 0.14-0.94, p = 0.036). Nebivolol has been found especially effective in preventing SVG graft occlusion (OR 0.24, CI 0.07-0.76, p = 0.015). Nebivolol has been found to reduce the frequency of graft occlusion following CABG, especially in case of SVG grafts. The vasodilatory properties of nebivolol may, at least in part, be responsible for the favorable effects of the drug to prevent graft occlusion.