BACKGROUND: Oils from marine organisms have a different fatty acid composition. Fish oil (FO) has a high content of eicosapentaenoic and docosahexaenoic acids esterified to triacylglycerols; while in krill oil (KO), fatty acids are primarily esterified to phospholipids. This study aimed to compare the efficacy of two different, marine-derived omega-3 fatty acid sources in the wound healing of colon anastomoses rat model. METHODS: For the study, we used 42 male Wistar albino rats. The rats were divided into six groups with seven rats in each group-CO3: left colonic anastomosis (control group), sacrificed on the third day; KO3: left colonic anastomosis + oral KO, sacrificed on the third day; FO3: left colonic anastomosis + oral FO, sacrificed on the third day; CO7: left colonic anastomosis (control group), sacrificed on the seventh day; KO7: left colonic anastomosis + oral KO, sacrificed on the seventh day; FO7: left colonic anastomosis + oral FO, sacrificed on the seventh day. Peritoneal adhesions, anastomotic bursting pressures, hydroxyproline levels, and histological examination of the anastomotic tissue were evaluated. RESULTS: On day 7, bursting pressure and hydroxyproline measurements of the KO group was significantly higher than the FO group (p=0.012; p=0.002, respectively). Also, on day 7, a statistically significant difference was observed between the groups according to inflammatory cell infiltration, fibroblast activity, neoangiogenesis, and collagen deposition in favor of the KO group (p=0.023; p=0.028; p=0.016; p=0.012, respectively). CONCLUSION: Both KO and FO supplementation in patients before colorectal surgery may reduce some risk of anastomotic leakage; and KO might be a better alternative and excellent omega-3 source.