Background: In myocardial revascularisation procedures, the underutilisation of the right internal mammary artery remains a concern. This study aimed to compare outcomes between using the right internal mammary artery (RIMA) and the great saphenous vein (GSV) as secondary conduits in Coronary Artery Bypass Grafting (CABG), focusing on early and mid-term postoperative results. Methods: A retrospective analysis of 270 patients who underwent CABG between November 2015 and January 2023 at Mohamed VI University Hospital was conducted. Patients were divided into RIMA and GSV groups for comparative analysis. Results: There were no significant differences in the preoperative characteristics of the study population. Patients in the RIMA group had lower cardiopulmonary bypass time and aortic cross-clamping time (110.70±34.08 vs 127.45±31.17: p<0.00 and 77.67±26.31 vs 82.93±23.66: p<0.00, respectively). The use of GSV was associated with more significant bleeding compared to RIMA (570.46±403.66 vs 761.40±647: p<0.00). However, there were no significant differences in the occurrence of deep sternal wound infection (3.24% vs 4.31%: p=0.8945) between the two groups. Regarding early mortality rates, there was no significant difference observed (5.19% vs 2.58%: p=0.4458). Mid-term results showed no difference in the recurrence of angina and dyspnea between the groups. Conclusion: The study indicated that RIMA used as a secondary graft in CABG wasn't linked to sternal wound infection or bleeding, suggesting its superiority as a graft choice. The findings aligned with prior research, advocating for the benefits of employing RIMA in myocardial revascularization.