Objectives: We hypothesize that nonpediatric and pediatric residents are exposed to a very low percentage of critically ill patients in a high-volume children's hospital emergency department (ED). Methods: Retrospective chart review of resident-patient encounters during a 1-year period using a patient tracking system. Critically ill patients included those who were triaged as "critical," died in the ED, or admitted to the intensive care unit. Descriptive data are presented as means +/- SD, frequencies, and percentages. Analysis of variance was used for continuous data and the chi(2) test for categorical data. Results: A total of 3048 (4.2% of the total ED volume) critically ill patients with a mean age of 6 (+/- 5.6) years were evaluated. One hundred four emergency medicine (EM) residents were involved in the care of 903 (30%), 136 pediatric residents managed 2003 (65%), and 36 family medicine residents managed 142 (5%) critically ill patients. There was no significant difference in the mean age of evaluated patients compared by type of training program. On average, EM residents evaluated 5 patients per 10 shifts compared with pediatric residents ([9 patients per 10 shifts] P < 0.0001). Unlike pediatric residents, the number of patients cared for by EM or family medicine residents did not increase with the level of resident training. Sixty-seven life-saving procedures were performed, of which 32 (48%) were cardiopulmonary resuscitations and 35 (52%) were intubations. Conclusions: Pediatric and nonpediatric residents who rotate through a high-volume children's hospital ED are exposed to a very low number of critically ill children. Other educational formats, such as mock resuscitations or standardized patient encounters, may be required to correct this deficit.