For many decades open surgery remained the only way available for local control of body tumors. In order to decrease the patients' morbidity and mortality several image guided minimally invasive procedures have been adopted. High intensity focused ultrasound (HIFU) is an extracorporeal non invasive method for tumor ablation. High intensity ultrasonic waves can be focused to a focal point resulting in lethal elevation of the temperature at the target site with consequent damage of the tumoral cells. The advances in HIFU technology during the past two decades expanded the HIFU applications to include ablation of both benign and malignant tumors with different treatment strategies being implemented for each type. The aim of this review is to introduce the reader to the details of the treatment process including pretreatment preparation, treatment planning, different ablation strategies, patients' after care as well as the follow up regimens for the most common HIFU applications.