Sixteen patients with pulmonary arteriovenous malformations (PAVM) have been treated by percutaneous transvenous coil embolization. In the ten patients who have had all their angiographically demonstrable PAVM's embolised there has been a reduction of right to left shunting from a mean of 28.1% to 13% and an improvement in mean arterial oxygen saturation from 87.4% to 92.4%. Eight of these ten patients now have oxygen saturations of more than 90%. All patients have shown symptomatic improvement. There have been three complications relating to the embolizations, none of which has been serious. Coil embolization of PAVM's is an effective, safe and well tolerated procedure. Embolization should be performed in all cases of PAVM's to prevent paradoxical embolization.