Of 547 men and 56 women enrolled up to April 1974 in Cardiopulmonary Research Institute (CAPRI) community programs for cardiopulmonary rehabilitatation, 84.5 percent had clinical manifestations of coronary heart disease. These medically supervised programs of physical training involved 30 to 60 minutes of graded levels of working, calisthenics and, if indicated, jogging for 3 mornings/week. Altogether 352 (58.4 percent) dropped out after an average of 8.6 months for men and 5.7 months for women. The remaining 230 men and 21 women remained active for 22 and 20 months, respectively. In retrospect, there were few minor differences between active participants and dropouts in physical characteristics, clinical diagnoses and responses to exercise testing on enrollment. Elapsed time to morbidity tended to be longer in active persons than in dropouts. Over one half of active men and about one third of dropouts were working. Of six early deaths, one occurred before training was instituted, and five within the first 2 weeks of training. Among men, the respective total mortality rates were 2.7 and 4.7/100 person-years for active participants and dropouts; among women, the rates were 0 and 3.8 respectively. Whereas 24 episodes of cardiac arrest occurred in 13 men, with three fatalities outside the training program, in 11 instances of exertional arrest during class training all defibrillations were successful. Without this benefit of medical supervision there would have been little difference in mortality experience.