Aim: The aim of this study was to investigate the risk and predictors of 30-day emergency readmission and surgical reintervention after discharge from colorectal cancer surgery with curative intent in Denmark. Method: This is a retrospective cohort study using Danish nationwide registry data. We included all patients who underwent colorectal tumour resection with curative intent between 1 January 2005 and 1 December 2018. The primary outcome was 30-day emergency readmission, defined as any emergency hospital visit within 30 days of discharge. Secondary outcomes were 30-day emergency readmission with a minimum duration of 2 days and 30-day emergency readmission including any abdominal procedure. Twenty-three candidate predictors including patient comorbidities, tumour characteristics, surgical treatment and length of stay were evaluated using multivariate logistic regression models. Length of stay was categorized into percentiles and standardized according to year of surgery. Results: Of the 40 782 patients included in the study, 8360 (20.5%) were readmitted within 30 days of discharge. Median time to readmission was 6 days (interquartile range 2–15 days). A total of 4968 patients (12.2%) were readmitted for at least 2 days, and 793 patients (1.9%) underwent an abdominal procedure during their readmission. The strongest predictors of 30-day readmission were length of stay below the fifth percentile (OR 2.36; P < 0.001) and American Society of Anesthesiologists score IV (OR 2.21; P < 0.001). Conclusion: Emergency readmission is frequent after colorectal cancer surgery with curative intent, and almost 10% of readmitted patients require surgical reintervention. An increased focus on predicting preventable readmissions might facilitate interventions to reduce morbidity and hospital expenses.