Objective and quantitative methods were used to measure severity of illness and outcome of intensive care in critically ill patients, in terms of success or failure of therapy within the ICU, survival or death at 1 yr, quality of life in survivors, and utilization of resources. One hundred ninety-nine consecutive Class IV critically ill surgical patients hospitalized between 1977 and 1978 at the Massachusetts General Hospital comprised the study population. Although the mortality rate of 69% was close to the 73% rate we recorded for 1972-1973, the survivors' quality of life was significantly better. Hospitalization costs increased from $15,000 to $22,000 per patient, almost consistent with the inflation rate between 1973 and 1978. Survival rates and quality of life in survivors did not vary with age. The disease process for which the patient was hospitalized was an important determinant of outcome. Intensive care medicine for critically ill surgical patients does prolong life and enable some patients to return to a productive lifestyle; however, the costs of these benefits are extremely high.