Background The Danish Colorectal Cancer Group (DCCG) established a national clinical database in 2001 with the aim to monitor and improve outcome of colorectal cancer patients. Since 2000 several national initiatives have been taken to improve cancer outcome. In the present study we used DCCG data to evaluate mortality and survival of CRC patients with focus on comorbidity, stage, and perioperative treatment. Material and methods Patients notified to the DCCG database from 2001 to 2012 were included. Patients with primary cancer of the colon and rectum were analyzed separately. Analyses were stratified according to gender, comorbidity, Union for International Cancer Control (UICC) stage, and operative priority (elective/emergency/no surgery). Data were stratified into three time periods (2001-2004, 2005-2008, 2009-2012). Mortality and survival were age adjusted. Results In total 29 385 patients with colon cancer and 15 213 patients with rectal cancer were included. The stage distribution was almost stable over time. The mortality rate per 100 patient year within one year decreased from 32 to 26 in colon cancer and from 26 to 19 in rectal cancer with associated improvements in absolute survival from 73% to 78% in colon cancer and from 78% to 83% in rectal cancer. The five-year relative survival of colon cancer improved from 58% to 63% and in rectal cancer from 59% to 65%. Comorbidity had major negative impact on outcome. Irrespective of tumor location, outcome improved relatively more in patients with stage III and IV disease. The proportion of patients who were spared surgery increased from 8% to 15% in colon cancer and from 13% to 19% in rectal cancer, and these changes were associated with improved outcome for rectal cancer patients, whereas outcome worsened for colon cancer patients. Conclusion The Danish efforts to improve outcome of cancer have succeeded with improved outcomes in patients with colorectal cancer.