This study compared hand-held arterial compression with compression by a mechanical clamp to achieve hemostasis following transfemoral catheterization in 3,255 patients from six different hospitals. The time spent in manual compression of the artery averaged 33.5 minutes compared with 19.9 minutes using the clamp. The incidence of hematoma formation using the manual method was 6%; it was 2% using the mechanical device. No ischemic symptoms or complications resulted from the use of the holding device. The results suggest that the mechanical method is an effective and time-saving alternative to manual compression for control of bleeding after transfemoral catheterization.