Objective This study compared all patients undergoing surgery for colorectal cancer in 20 hospitals of Northern Italy in 2019 versus 2020, in order to evaluate whether COVID-19-related delays in the execution of colorectal cancer screening resulted in more advanced cancers at diagnosis and worse clinical outcomes. Design A retrospective multicentric cohort analysis of patients who underwent surgery for colorectal cancer in March-December 2019 (2019) versus March-December 2020 (2020). The independent predictors of disease stage (oncologic stage, associated symptoms, clinical T4 stage, metastasis) and postoperative outcome (surgical complications, palliative surgery, 30-day death) were evaluated using logistic regression. Results The sample consisted of 1755 patients operated in 2019, and 1481 in 2020 (both mean ages 69.6 years). The proportions of cancers with symptoms, clinical T4 stage, liver and lung metastases in 2019 and 2020 were, respectively: 80.8% vs 84.5%; 6.2% vs 8.7%; 10.2% vs 10.3%; and 3.0% vs 4.4%. The proportions of surgical complications, palliative surgery, and death in 2019 and 2020 were, respectively: 34.4%vs 31.9%; 5.0% vs 7.5%; and 1.7% vs 2.4%. At multivariate analysis, as compared with 2019, cancers in 2020 were significantly more likely to be symptomatic (Odds Ratio - OR: 1.36, 95% Confidence Interval - CI: 1.09-1.69), in clinical T4 stage (OR: 1.38; 1.03-1.85), with multiple liver metastases (OR: 2.21; 1.24-3.94), but less likely to cause surgical complications (OR: 0.79; 0.68-0.93). Conclusions Colorectal cancer patients who had surgery between March and December 2020 had an increased risk of more advanced disease in terms of associated symptoms, cancer location, clinical T4 stage, and number of liver metastases.