To evaluate the safety and efficacy of a new pneumatic compression device for achieving haemostasis after femoral artery catheterization, 1,017 patients undergoing selective coronary angiography by a 5F unilateral femoral route were prospectively randomised to pneumatic or the routinely used clamp compression technique. All initial bleedings could be controlled in the pneumatic group, whereas in 38 patients (8%) of the clamp group the initial positioning of the clamp was unsuccessful or was not tolerated by the patient (p < 0.05). Ultrasound Doppler study of the puncture site because of suspected postcatheterization vascular complication revealed two haematomas which needed no further measure and two pseudoaneurysms which were successfully treated with ultrasound-guided compression or surgical repair. The rate of complications requiring treatment (pseudoaneurysms) was 0.2% overall, 0.5% in the clamp group and nil in the pneumatic compression group (NS). We conclude that the pneumatic compression device is effective, convenient and at least as safe as the clamp and, by shortening the time in the catheterization laboratory, offers time for further angiograms.