Background: We described changes in treatment of colon cancer over time and the impact on survival in The Netherlands in the period 1989-2006. Patients and methods: All 103 744 patients with invasive colon cancer during 1989-2006 in The Netherlands were included. Data were extracted from The Netherlands Cancer Registry. Trends in treatment over time were analysed and multivariable relative survival analysis was carried out. Results: The administration of adjuvant chemotherapy in stage III patients <75 years increased from 19% in 1989-1993 to 79% in 2004-2006 and from 1% to 19% in stage III patients >= 75 years. Among stage IV patients, resection rates of the primary tumour decreased from 72% to 63%, while chemotherapy administration increased from 23% to 64% in those <75 years. Survival increased from 52% to 58% in males and from 55% to 58% among females. Stage III patients with adjuvant chemotherapy exhibited a relative excess risk of 0.4 (95% confidence interval 0.4-0.4) compared with those without. Among stage IV patients, resection of primary tumour, palliative chemotherapy, and metastasectomy were important prognostic factors. Conclusions: There were substantial improvements in management and survival of colon cancer from 1989 to 2006. Stage III disease patients with colon cancer experienced the largest improvement in survival, most likely related to the increased administration of adjuvant chemotherapy.