This is a revision of the 1976 report published under the auspices of the Inter-Society Commission for Heart Disease Resources. These guidelines provide a description of optimal resources, personnel, and working arrangements and should not be used to set minimal, standard, or uniform criteria or practices for all institutions. Included in the report are specifications for radiologic and physiologic equipment, description of case loads for maintaining safe and effective performance and considerations or complication rates. Also discussed are professional staff qualifications and relationships between physicians and technical and administrative services personnel. Other topics reviewed included laboratory location, electrical safety, and radiation protection as well as optimal facilities and equipment criteria for conventional x-rays. Newer imaging modalities are briefly considered, primarily to to emphasize that the field is rapidly changing. It is not possible, however to make specific recommendations concerning how these modalities will complement and/or replace more conventional techniques and approaches now considered appropriate and optimal.