Femoral artery pseudoaneurysm is a common complication associated with cardiac catheterization procedures. Ultrasound-based techniques (e.g., mechanical compression, thrombin injection) and open surgical intervention are frequently used in the management of pseudoaneurysm. The investigators report their prospective experience with a novel method for the treatment of pseudoaneurysm after cardiac catheterization using ultrasound-guided, para-aneurysmal injection of physiologic saline. Sixty-four consecutive patients with pseudoaneurysms after cardiac catheterization were treated using normal saline (0.9% sodium chloride 25 to 60 ml) injected into the tissue surrounding the tract connecting the pseudoaneurysm with the femoral artery, followed by manual pressure of short duration. In none of the patients was concomitant antithrombotic therapy (aspirin [n = 63], clopidogrel [n = 45], unfractionated or low-molecular-weight heparin [n = 23], and warfarin [n = 5]) discontinued during the closure attempt. Fifty-nine of the 64 pseudoaneurysms (92%) were successfully occluded using saline injection. In 5 patients in whom saline injection failed, the pseudoaneurysms were successfully treated with thrombin injection (n = 4) or ultrasound-guided compression (n = 1). In all 64 patients, pseudoaneurysm closure was confirmed by ultrasound at 24 hours. The procedure was very well tolerated by the patients, and no side effects or complications were noted. In conclusion, ultrasound-guided saline injection affords a simple, safe, and effective alternative treatment for the closure of postcatheterization pseudoaneurysms.