BACKGROUND Radical resection is the only long-term cure for malignant liver tumours. An important contraindication for surgery is that the liver remnant would be too small. Embolization of the portal vein in the tumour-bearing side of the liver may induce growth of the healthy part and thereby render liver resection possible. METHODS 18 patients, aged 35 - 71 years, underwent portal vein embolization in the period 2002 - 2006. An interventional radiological percutaneous transhepatic technique was used. RESULTS The liver remnant increased with 45 % (median), range 9 - 100 %, in all patients. Liver resection could be done and was performed in 10 patients. Due to tumour progression, resection could not be done in seven patients. One patient was excluded from surgery due to serious side effects of chemotherapy. Four-year survival for patients with metastases from colorectal cancer (n=9) was 58 %. CONCLUSIONS Portal vein embolization results in a substantial increase of liver volume. The technique effectively increases the number of patients eligible for liver surgery. It is possible for patients treated with this technique to obtain the same long-term survival as those primarily regarded to be operable. Advanced radiological technology is needed to exclude patients who would not profit from the procedure.