Patients undergoing surgery for colorectal cancer are at high risk of post-operative venous thromboembolism (VTE). Thromboprophylaxis has been shown to have significant risk reduction, although there remains some controversy surrounding the optimal duration of pharmacological prophylaxis. Our institution does not routinely practise extended prophylaxis. The aim of this study was to retrospectively review the rate of post-operative thromboprophylaxis in colorectal cancer patients, and incidence of symptomatic VTE. Methods: We conducted a retrospective audit of 200 consecutive patients who underwent colorectal surgery for cancer. Data to 90 days post-operatively were collected from medical records and imaging and phone calls to patients and family practitioners. Results: Of the patients, 98 received pharmacological prophylaxis, with a median duration of eight days. Eight (4 ) symptomatic VTEs were diagnosed within the 90-day follow-up period: two deep vein thrombosis (DVTs), five pulmonary emboli (PE) and one patient with both PE and DVT. A higher proportion of patients developed DVT/PE if they received prophylaxis other than low molecular weight heparin and similarly there was a trend in increased risk of DVT in the presence of metastatic disease. However, using univariate analysis, these results were not statistically significant (P = 0.18 and 0.11, respectively). Discussion: The use of thromboprophylaxis was high in our centre, and the incidence of VTE was low when patients received a median of 8 days pharmacological prophylaxis combined with mechanical prophylaxis. The VTE incidence of 4 is similar to previous studies using extended prophylaxis. Our study findings do not support changing local protocol to extended prophylaxis.