The aim of this study was to evaluate the safety of transradial catheterization without prior withdrawal of oral anticoagulation. In total, 183 patients on long-term acenocoumarol treatment who underwent transradial catheterization were included in a prospective study. In 135 patients, the coumarin derivative was continued without interruption before and during catheterization and, in 48, the drug was stopped 48 hours in advance. No severe thromboembolic or hemorrhagic complications occurred. At 7-day follow-up, the rate of occurrence of hematomas >3 cm in size was 5.5% in the group that continued anticoagulant treatment, and 10.4% in the group that stopped oral anticoagulation (P=.31). The transradial approach appears to be a safe option for patients receiving long-term coumarin treatment and could be the technique of choice because it avoids the drawbacks and complications associated with the withdrawal of oral anticoagulation.