Aim: Both the Danish and the National Institute of Clinical Excellence (NICE) guidelines recommend prolonged thromboprophylaxis (PT) with low-molecular-weight heparin (LMWH) for 28 days postoperatively after elective surgery for colon cancer. The evidence relies on data from two randomized clinical trials (RCTs) that included not only colon cancers but also other abdominal cancers or benign colorectal diseases. Neither of those studies investigated the risk of venous thromboembolism (VTE) under enhanced recovery after surgery (ERAS). We aim to describe the risk of VTE and estimate the cost of preventing one case of VTE by PT under ERAS. Method: This was a retrospective study of 2230 patients undergoing elective surgery for colon cancer Stage I-III in the Capital Region of Denmark, 1 June 2008 to 31 December 2013. Patients who were discharged on postoperative day 28 or later, died during admission or were discharged with a vitamin K antagonist, novel oral anticoagulants or LMWH were excluded. Patients with rectal cancer only were not included. End-points were symptomatic VTE diagnosed within 60 days postoperatively. Results: Three-hundred and thirty patients were excluded. For the remaining 1893, the median length of stay (LOS) was 4 [interquartile range (IQR): 3–5] days. Of these 1893 patients, four (0.20%) experienced a nonfatal symptomatic VTE. All four patients had other postoperative complications before the VTE. The cost of each symptomatic VTE prevented is estimated to be between £63 709 and £111 455 when medication and home-care nursing are included. Conclusion: The risk of symptomatic VTE after uncomplicated, elective surgery for colon cancer with ERAS seems negligible and the cost-effectiveness of PT to prevent one symptomatic VTE seems questionable.