Background: The aim was to assess factors influencing the timing of defunctioning stoma (DS) reversal following low anterior resection of rectum for cancer (LAR). Methods: All patients operated with LAR and a primary DS during a 9-year period were included. Reversal later than 120 days after LAR was considered as delayed. A DS not reversed within 2 years was considered as permanent.Results: In the present study, median age at LAR was 67 years, 45% were females, median body mass index was 25, 87% had American Society of Anesthesiologists class I or II, 64% had pre-operative radiotherapy, and 3% had cancer stage IV. A total of 79% (92/116) underwent stoma reversal, whereof 25% (23/92) were reversed within 120 days. The most common health-related reasons for delayed stoma reversal were adjuvant chemotherapy in 38%, symptomatic anastomotic leakage in 16% and other post-operative adverse events in 13%. In 35% delayed stoma reversal was because of low priority within the healthcare system. A total of 18% (20/110) never had their DS reversed (n = 11) or had their DS converted to a permanent end colostomy (n = 9). Major risk factors for permanent stoma were stage IV cancer in 55%, and symptomatic anastomotic leakage in 30%. Conclusion: One fourth of the patients had their defunctioning stoma reversed within 120 days. The most common identifiable medical reasons for delayed stoma reversal were adjuvant chemotherapy and symptomatic anastomotic leakage, while in one out of three patients it was because of low priority by the healthcare provider.