Pseudoaneurysm is a well-recognized complication of invasive arterial procedures that is easily diagnosed with ultrasound. While most pseudoaneurysms will be resolved spontaneously within 3 months, some may lead to limb swelling, ischemia, thromboembolism, or nerve damage. To forestall such complications, we attempted to close the lesion using ultrasound to guide application of pressure in 13 patients with pseudoaneurysms following arterial catheterizations. Successful closure averaged 64 minutes (range 20-180) with successful results achieved in 11 (85%) of the 13 patients. No complications followed the application of either manual or device-assisted pressure. We conclude that transcutaneous compression is a generally safe and successful treatment of uncomplicated pseudoaneurysm and should be used as the treatment of choice for this lesion. (ECHOCARDIOGRAPHY, Volume 13, September 1996)