Anticoagulants and antiplatelet agents commonly are used to treat patients with cardiovascular and cerebrovascular diseases. Data on the safety of the use of these drugs before colonoscopic polypectomy are scanty. An audit was conducted for a 2-year period of consecutive patients undergoing colonoscopy and polypectomy. Patient demographics, site and size of polyps, and the use of anticoagulants and antiplatelet agents were documented from a hospital on-line database. Bleeding episodes were classified as immediate or delayed and were graded as mild, moderate, or severe. Risk factors associated with postendoscopy bleeding were analyzed by multivariate logistic regression analysis. A total of 5593 cases were reviewed. Polypectomy was performed in 1657 patients. There were 37 cases of polypectomy-associated bleeding (2.2%); bleeding was immediate in 32 and delayed in 5. Multivariate analysis showed that warfarin use, after adjustment for the effects of each of the other factors, was an independent risk factor for bleeding, with an odds ratio 13.37: 95% CI[4.10, 43.65]. Age; the location and size of polyp; and the use of aspirin, non-steroidal anti-inflammatory drugs, and other antiplatelet agents were not associated with a higher risk of polypectomy-associated bleeding. The use of antiplatelet agents during polypectomy was not associated with an increase in post-polypectomy bleeding. In contrast, treatment with warfarin should be discontinued, because this was associated with a significant increase in post-polypectomy bleeding.