Introduction: The aim of this study was to investigate the clinical outcomes between 2 groups of elderly rectal cancer patients according to the time duration after which their diverting stoma can be reversed. Methods: We recruited 124 patients who were ≥65 years old and had undergone diverting stoma after rectal cancer surgery. In Group 1, the reversal of the stoma was predominantly performed after the sixth adjuvant chemotherapy. In Group 2, the reversal was predominantly performed after the third adjuvant chemotherapy. Results: The mean duration for which patients had a stoma was 28.6 ± 9.9 weeks in Group 1 and 17.1 ± 7.4 weeks in Group 2. The interval between stoma formation and stoma formation-related complications was slightly longer in Group 1 than in Group 2 (13.5 ± 9.7 vs. 8.0 ± 4.9 weeks, p = 0.075). There were 16 stoma-related complications in Group 1 (23.2%) and 10 in Group 2 (18.2%) (p = 0.516). There were 6 stoma closure-related complications in Group 1 (8.8%) and 6 in Group 2 (10.9%) (p = 0.766). Discussion: This study shows that stoma closure during adjuvant chemotherapy is no more harmful than stoma closure after termination of adjuvant chemotherapy. Conclusion: It may be possible to limit the duration of diverting stoma following rectal cancer surgery, even if patients are elderly and undergoing adjuvant chemotherapy.