Objectives To evaluate how the certification of specialised Oncology Centres in Germany affects the relative survival of patients with colorectal cancer (CRC) by means of national and international comparison. Methods Between 2007 and 2013, 675 patients with colorectal cancer, treated at the Hildesheim Hospital, an academic teaching hospital of the Hannover Medical School (MHH), were included. A follow-up of the entire patient group was performed until 2014. To obtain international data, a SEER-database search was done. The relative survival of 148,957 patients was compared to our data after 12, 36 and 60 months. For national survival data, we compared our rates with 41,988 patients of the Munich Cancer Registry (MCR). Results Relative survival at our institution tends to be higher in advanced tumour stages compared to national and international cancer registry data. Nationally we found only little variation in survival rates for low stages CRC (UICC I and II), colon, and rectal cancer. There were notable variations regarding relative survival rates for advanced CRC tumour stages (UICC IV). These variations were even more distinct for rectal cancer after 12, 36 and 60 months (Hildesheim Hospital: 89.9, 40.3, 30.1%; Munich Cancer Registry (MCR): 65.4, 28.7, 16.6%). The international comparison of CRC showed significantly higher relative survival rates for patients with advanced tumour stages after 12 months at our institution (77 vs. 54.9% for UICC IV; raw p<0.001). Conclusions Our findings suggest that patients with advanced tumour stages of CRC and especially rectal cancer benefit most from a multidisciplinary and guidelines-oriented treatment at Certified Oncology Centres. For a better evaluation of cancer treatment and improved national and international comparison, the creation of a centralised national cancer registry is necessary.