Embolization is a vascular interventional procedure that employs various materials to obstruct the blood flow of a vessel or tumor. Embolization in oncologic patients serves a multitude of purposes, including the cessation of tumor or tissue blood flow by means of catheterization with various materials, the reduction of tumor size by creating ischemia through the coverage of the most distal region, and the mitigation of bleeding risk during surgery by the administration of preoperatively in hypervascular tumors. It is of great importance that the embolization targets the distal bed, as proximal embolization may cause neovascularization at a later stage, which may ultimately lead to failure of the technically correct procedure. Therefore, the choice of embolizing particles is a crucial step. The use of too large particles may result in proximal occlusion, whereas the use of too small particles may lead to mucosal necrosis, chronic pain, or unwanted tissue and/or organ embolization via microcollaterals. In this chapter, our objective is to provide a concise overview of embolizing agents and subsequently discuss embolization procedures in head and neck, renal, pelvic-gynecological, and bone tumors, respectively.