BACKGROUND: Arthrocentesis and joint injections are commonly performed for both diagnostic and therapeutic indications. Because of safety concerns, there is often reluctance to perform these procedures in patients who are receiving anticoagulation at therapeutic levels. This study was undertaken to determine the safety of arthrocentesis and joint injection performed by physicians from different disciplines in patients who are anticoagulated. METHODS: We conducted a retrospective review of 640 arthrocentesis and joint injection procedures performed in 514 anticoagulated patients between 2001 and 2009. We assessed the incidence of early and late clinically significant bleeding in or around a joint, infection, and procedure-related pain. We further compared the incidence of these complications in 456 procedures performed in patients with an international normalized ratio 2.0 or greater and 184 procedures performed in patients with an international normalized ratio less than 2.0. RESULTS: Only 1 procedure (0.2%) resulted in early, significant, clinical bleeding in the fully anticoagulated group. There was no statistically significant difference in early and late complications between patients who had procedures performed with an international normalized ratio 2.0 or greater and those whose anticoagulation was adjusted to an international normalized ratio less than 2.0. CONCLUSION: Arthrocentesis and joint injections in patients receiving chronic warfarin therapy with therapeutic international normalized ratio are safe procedures. There does not seem to be a need for reducing the level of anticoagulation before procedures in these patients.