The Yale University School of Medicine has carried on training programs for post-doctoral fellows in radiation biology and radiological physics for more than 40 years. The Department of Therapeutic Radiology has mounted a broadly based laboratory research program in radiation biology, cancer biology, molecular biology with a cancer emphasis, and radiological physics. The goal is to establish a balanced effort, which covers a broad spectrum of research activity from the molecular to the clinical level. The appeal of such a program is that it encourages rapid and efficient application of the results of basic research to clinical problems. It also stimulates cross-fertilization of ideas and techniques to enhance productivity and promote innovation. The research efforts in this program provide fertile ground to train and nourish new investigators who will carry the field forward in the coming decades. It is anticipated that work carried out in the trainers’ laboratories and by the trainees as they embark on their independent careers will illuminate basic mechanisms of cancer biology and will facilitate the translation of this understanding into new approaches to the treatment of cancer.