Résumé : Liver metastases represent the principal cause of death for patients with advanced colorectal cancer. Resection remains the only potentially curative treatment. Selective internal radiation therapy by means of the administration of yttrium-90 labeled resin microspheres (SIR-Spheres; Sirtex Medical Limited, Sydney, Australia) into the arterial supply of the liver is a local treatment option for patients with unresectable malignant liver tumors. We report the case of a patient with an unresectable liver colorectal metastasis refractory to chemotherapy downstaged to allow resectability after selective internal radiation therapy. © 2008 by Lippincott Williams & Wilkins.