Regional hyperthermia with a radiofrequency capacitive heating apparatus in combination with hepatic arterial embolization with degradable starch microspheres (DSM) was performed in 20 primary and six metastatic liver cancer patients. Efficacy was assessed primarily with regard to the improvement in heating efficiency. An angiocatheter was inserted into the hepatic artery in order to determine the DSM dosage adequate to arrest blood flow. The temperature rise in the tumours after heating alone and after heating combined with DSM embolization was compared. The maximum temperature and initial temperature rise within tumours were significantly improved by the combination therapy. Local tumour response could be evaluated in 10 primary and three metastatic liver cancer patients and tumour reduction over 50% was obtained in 40% and 33% respectively. Abdominal pain, nausea and vomiting, presumably due to reflux of the DSM, were experienced by several patients. In three patients heating could not be continued. However, all the symptoms were transient and responsive to symptomatic treatment, and no significant late complications were observed. Hepatic arterial embolization with DSM for liver tumours is considered effective and safe when combined with regional hyperthermia.