In May 1966, the work of an ad hoc Committee on Cardiopulmonary Resuscitation culminated in a Conference on Cardiopulmonary Resuscitation at the National Academy of Sciences-National Research Council (NAS-NRC). This study was undertaken in response to inquiries from the American National Red Cross and other national and federal agencies concerned with the need for standardized techniques of performance, training, and retraining requirements, and designation of the categories of persons to be taught mouth-to-mouth ventilation and external cardiac compression under present limitations on the supply of instructors. The ad hoc committee carefully reviewed and discussed these matters with representatives of over 30 national organizations attending the conference. The full proceedings of the conference will be published by the NAS-NRC. A summary of the recommendations of the ad hoc committee follows.