This review is based upon an appraisal of training research in psychotherapy showing that many questions are still unanswered. By means of a schema for the organization of research results that differentiates input, process and output variables, unselected results are summarized relating to issues such as the choice of the psychotherapeutic profession, pre-experiences of candidates, the selection of an orientation, personality factors, characteristics of training institutes, quality standards, as well as the organisation and structure of training programs. Process oriented studies mainly focus on the operationalisation and development of skills, the significance, the effects of and the satisfaction with training components. Finally, the output category comprises results related to graduation, to professional development during and following training and to the development of competence and its prediction.