The pseudoaneurysms are resulted from complication of vascular catheterization, trauma, etc. and recently, thereports on pseudoaneurysms have been increasing. Successful treatment of pseudoaneurysms have been described usingdirect compression guided by color doppler ultrasound, instead of invasive surgical treatment. Authors experiencedthree cases of pseudoaneurysm ; two resulted from post-catheterization and one from trauma. We successfullytreated two post-catheterization cases using C-clamp compression under the colordoppler US-guidance. The traumaticcase was treated by embolization instead of US-guided compression. We suggest that the compression ofpseudoaneurysm using C-clamp under the US-guidance is more useful than hand or probe compression method.