Artificial embolisation of the renal artery or its branches was performed in 48 patients with renal carcinoma. Occlusion was effected by using Gelaspon or Ivalon sponges, metal spirals or a combination of both. This surgical intervention created favourable conditions for surgery. In about 80% of the patients pain occurred after embolisation, whereas more than half of them had fever or subfebrile temperatures. The use of Gelaspon sponge is recommended as the simplest and cheapest method of preoperative embolisation. To cut short the unpleasant effects of the postembolisation syndrome it appears to be best to operate 24 hours after embolisation.