Background The territory of the right coronary artery (RCA) is smaller than that of the left anterior descending artery. Previous studies have reported conflicting results when considering whether stable RCA-chronic total occlusion (CTO) should be reopened. The coexistence of diabetic and coronary artery diseases represents a severe situation. Therefore, we aimed to determine if stable RCA-CTO in diabetic patients was necessary to be reopened. To our knowledge, no studies have focused on this topic to date. Methods We enrolled diabetic patients with RCA-CTO who had clinical presentations of symptomatic stable angina or silent ischemia. RCA-CTO was treated with either successful revascularization (the CTO-SR group) or medical therapy (the CTO-MT group). The primary endpoint was all-cause death. Both Cox regression and propensity score matching analyses were used. Sensitivity analysis was performed based on subgroup populations and relevant baseline variables. Results A total of 943 patients were included: 443 (46.98%) patients in the CTO-MT group and 500 (53.02%) patients in the CTO-SR group. After a mid-term follow-up (CTO-SR: 48 months; CTO-MT: 42 months), we found that CTO-SR was superior to CTO-MT in terms of all-cause death (adjusted hazard ratio [HR] [model 1]: 0.429, 95% conference interval [CI] 0.269-0.682; adjusted HR [model 2]: 0.445, 95% CI 0.278-0.714). The superiority of CTO-SR was consistent for cardiac death, possible/definite cardiac death, repeat revascularization, target vessel revascularization (TVR) and repeat nonfatal myocardial infarction. Subgroup analysis confirmed the mortality benefit of CTO-SR by percutaneous coronary intervention (the successful CTO-PCI subgroup, 309 patients in total). While CTO-SR by coronary artery bypass grafting (the CTO-CABG subgroup, 191 patients in total) offered patients more benefit from repeat revascularization and TVR than that offered by successful CTO-PCI. Conclusions For stable RCA-CTO patients with diabetes, successful revascularization offered patients more clinical benefits than medical therapy. CTO-CABG might be a more recommended way to accomplish revascularization. Trial registration This study was not registered in an open access database