The common femoral artery is commonly used as arterial access for a wide range of radiological and cardiological procedures. Pseudoaneurysm formation is the most common arterial complication of femoral artery catheterization, and is diagnosed using colour Doppler ultrasound. Ultrasound-guided thrombin injection has replaced ultrasound-guided compression as the first-tine treatment. The practicalities of thrombin injection (technique and types of thrombin available) and other treatment options are discussed. Awareness of pseudoaneurysm formation and the treatment options allows prompt diagnosis and successful treatment. (C) 2008 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.