Background: About one third of patients racically resected for colorectal cancer develop during follow-up recurrence. Materials and methods: There were 1951 patients operated for colorectal cancer in Surgical Department, Thomayer Hospital Prague, from 1997 to 2015. Radical R0 operation underwent 68% of these patients. Postoperative complications occurred in 457 (34.6%) patients. Impact of postoperative complications on disease free interval was studied in a prospective study. Results: We identified minor complications in 90 patients (6.8%), moderate complications in 28 patients (2.1%), anastomotic leakage in 67 patients (5%) and severe septic complications in 20 patients (1.5%). Another 255 patients (19.3%) had a different, non-inflammatory complications (pulmonary embolism, bowel obstruction, heart failure, etc.). Significantly worse disease-free interval was found in patients with severe septic complications. Conclusion: In our cohort of R0 operated patients, postoperative complication is the second most important prognostic factor following TNM stage of the colorectal cancer. Severe septic complications has an adverse effect on the further course of the disease in terms of relapse. Other potentially septic complications such as anastomotic leakage have no essential impact on recurrence. Therefore, it is necessary to prevent the development of sepsis.