A retrospective analysis of the caloric intake of patients in the coronary intensive care unit was undertaken after discovery of two cases of severe hypoglycemia. An unsuspected number of extremely low daily caloric intakes were found after careful analyses. The surviving group (50 patients) had less than 600 calories on 19.5% of the patient days and under 800 calories on 28.8% of patient days. In the nonsurviving group (29 patients) caloric intake was under 600 calories on 48.8% of patient days and under 200 calories on 22.7% of patient days. This study indicates the importance of monitoring actual caloric intake to avoid unrecognized extreme caloric deprivation and its possible complications.