The Institute of Oncology was founded in 1938, and at that time, it was one of the few comprehensive cancer centres in the world. It gradually grew and developed into a major cancer centre in Slovenia, maintaining its role of a functional comprehensive cancer centre. The professional work is based on a high-quality multidisciplinary approach to diagnosis and treatment. The Institute is the central institution that partially performs, and at a national level, directs the programs of comprehensive cancer care in the fields of prevention, early detection, treatment and rehabilitation.