Purpose We evaluated the short-term and mid-term differences in perfusion and function after off-pump and on-pump coronary artery bypass grafting (CABG) using gated myocardial single photon emission computed tomography. Materials and Methods A total of 70 patients with coronary artery disease who underwent CABG were included based on the propensity score matching results from 165 patients. Thirty-five patients underwent off-pump and 35 patients on-pump CABG. Rest $^{201}Tl$/dipyridamole stress $^{99m}Tc$-methoxyisobutylisonitrile gated single photon emission computed tomographies were performed preoperatively and postoperatively at short-term ($103{pm}23$ days after surgery) and mid-term follow-up ($502{pm}111$ days after surgery). Changes in left ventricular ejection fraction, end systolic volume, stress and rest segmental perfusion, and segmental wall thickening were compared between the two groups. The segments with preoperative rest $^{201}Tl$ uptake under 60% of maximum uptake were included in the segmental analysis. Results Left ventricular ejection fraction (P=0.001) and end systolic volume (P=0.008) showed significant improvement in both groups. There were no significant short-term and mid-term differences between the two groups in terms of left ventricular ejection fraction (P=0.309) and end systolic volume (P=0.938). Likewise, segmental rest (P=0.178) and stress perfusion (P=0.071), and systolic wall thickening (P=0.241) showed significant improvement in both groups with similar time courses. Conclusion Off-pump CABG resulted in significant improvements in left ventricular ejection fraction, end systolic volume, and regional myocardial perfusion and function that are comparable to on-pump CABG at shortterm and mid-term. Gated myocardial SPECT successfully revealed that off-pump CABG is as good as on-pump CABG from the viewpoint of myocardial perfusion and function.