We have developed a protocol for nonoperative management of pseudoaneurysms and arteriovenous fistulas secondary to cardiac catheterization. Hemodynamically stable patients were placed at bed rest and underwent serial physical examination, hematocrit, and duplex ultrasonography for a minimum of three days prior to discharge and subsequently as outpatients. Sixteen initially stable patients out of 56 with femoral artery catheter trauma managed over a four-year period underwent deliberate conservative management. Their lesions included six arteriovenous fistulas, seven pseudoaneurysms, and three patients with both complications. All but one of the pseudoaneurysms resolved spontaneously within four weeks regardless of initial size or associated arteriovenous fistula. One patient receiving anticoagulant therapy required surgery for bleeding after a three-day period of observation of a pseudoaneurysm. Six of the nine arteriovenous fistulas also resolved within the initial period of observation. The remaining three have been followed for four to 20 months and have remained asymptomatic. Nonoperative therapy of catheter-related femoral artery trauma is both safe and effective. Conservative management avoids potential wound complications associated with dissection through surrounding hematoma as well as the additional hospitalization required for postoperative care. We recommend a period of observation for all hemodynamically stable patients with catheter-induced pseudoaneurysms and arteriovenous fistulas of the femoral vessels, with surgery reserved for hemorrhage, expanding masses, or compromised cardiac output.