Low saphenous vein graft (SVG) patency has become the bottleneck in surgical revascularization. This study aimed to identify the predictors of early vein graft failure (VGF) after off-pump coronary bypass grafting (OPCAB). A total of 233 patients who had OPCAB were postoperatively evaluated by coronary computed tomography angiography. Logistic regression analyses were performed to detect the predictors of early VGF (FitzGibbon-B/O) at both the patient and the graft level. Overall FitzGibbon-A patency of SVG at 1 week after OPCAB was 94.1% (659/700). At the patient level, a patient who had at least 1 VGF was regarded as an event, and increased preoperative platelet count [odds ratio (OR) 9.848], quantity of perioperatively transfused red blood cells (RBC) (U, OR 1.544) and creatinine clearance rate (CCr) (ml/min, OR 1.037) were predictors of early VGF, whereas use of a left internal mammary artery graft was a protective factor (OR 0.348). At the graft level, when VGF was regarded as an event, increased preoperative platelet count (OR 17.450), CCr (ml/min, OR 1.034), quantity of perioperatively transfused RBC (U, OR 1.505) and endarterectomy (OR 5.499) were predictors of early VGF. Under the same circumstances, dual antiplatelet therapy (OR 0.419), recipient vessel diameter (mm, OR 0.052), graft run-off (ml/min, OR 0.949), preoperative RBC count (×1012, OR 0.576) and a side-to-side (when compared with end-to-side) anastomosis (OR 0.276) were protective factors. The patency of SVGs sutured to vessels with a larger diameter (>1.5 mm) was significantly higher than that of the others (96.6% vs 91.1%). SVGs with greater run-off (>25 ml/min for each anastomosis) were significantly more patent than others (95.1% vs 88.7%). Early SVG patency after OPCAB was satisfactory. Increased preoperative platelet count, more perioperative RBC transfusions and higher CCr were predictors of patients with early VGF, whereas use of a left internal mammary artery graft was a protective factor. Increased preoperative platelet count, higher CCr, more perioperative RBC transfusions and endarterectomy were predictors of VGF, whereas dual antiplatelet therapy, larger recipient vessel diameter, greater graft run-off, higher preoperative RBC count and side-to-side anastomosis were protective factors. Recipient diameter >1.5 mm and graft run-off >25 ml/min were cut-off values for detecting VGF.