Although curative treatment is surgery (resection/transplantation) and for small lesions ablative strategies, in primary liver carcinomas such as hepatocellular carcinoma and cholangiocellular carcinoma, palliative treatment is used for most of these patients because of lack of surgical options. These treatments are regional treatments such as transarterial chemoembolization, radiofrequency ablation, or microwave ablation and systemic treatments such as tyrosine kinase inhibitors. Surgery and chemotherapy are the main treatment options for metastatic liver tumors, particularly in colorectal tumors, although local treatment options are used for these patients. In recent years, transarterial radioembolization with yttrium-90 microsphere has emerged as a local treatment option in primary and metastatic liver tumors. The aim of this treatment is to provide an effective radiation dose distribution for the tumor in the liver tissue and to give the lowest dose in order to not harm the intact liver tissue. Radioembolization has proven to be as effective as other available palliative treatments in primary and secondary liver tumors and is a treatment method that is well tolerated. It has a risk for serious life-threatening complications, although this rate is low. Toxicity can be kept at a minimum with adequate technical and rigorous application in experienced hands and in accordance with multidisciplinarity. It is hoped that the effectiveness of radioembolization is further increased in the future by technological developments, researches on dosimetry, its use along with radiosensitizing agents, and various treatment combinations.