- Background The aim of this study was to determine whether the outcome of patients with colorectal cancer who presented with bleeding and a history of anticoagulant treatment was different from those who did not have bleeding or previous anticoagulant treatment. Methods This was a single institution, retrospective study of patients with colorectal cancer with and without a history of rectal bleeding and treatment with anticoagulants, assessed for age, gender, tumor site, stage, recurrence rate, and survival. Results A total of 621 consecutive patients (309 men) with a mean age of 70 years (range, 36–44 years) diagnosed with colorectal cancer between 1998 and 2004 were studied. Of these, 149 patients (24%) were referred for symptoms of rectal bleeding and 161 patients (26%) had been previously treated with anticoagulants. A total of 592 patients (95%) underwent curative or palliative surgery; endoscopic polypectomy was performed in 3 cases only and in 26 patients (4%) surgery was not performed due to advanced disease or critical illness. Patients with bleeding and a history of anticoagulant treatment presented commonly with stage I cancer. In addition, tumor stage III was less common in patients with previous anticoagulant treatment irrespective of presenting signs. Disease-free and overall survival rates were similar in all groups, irrespective of bleeding at presentation or anticoagulant treatment. Conclusions Rectal bleeding and anticoagulant treatment do not affect the outcome of newly diagnosed patients with colorectal cancer.