The purpose of the study was to assess the knowledge of physicians in training about child safety seats and to test the effectiveness of a brief didactic session on improving that knowledge. Pre-post quasi experimental design was used. A 25-minute didactic session on the need for and appropriate use of child safety seats was presented. Subjects took a multiple-choice test before and immediately after the lecture. Tests were scored and baseline differences as well as differences in score improvements were analyzed by subgroup. Basic fund of knowledge was poor with a mean pretest score of 54%. Mean posttest score improved to 81.5% (P [lt ] .001). The only significant difference among groups was that pediatric residents had higher pretest scores (65%, P [equals] .011), than their colleagues in other specialties. Medical students and residents in many specialties, including emergency medicine, have little baseline knowledge on the appropriate use of child safety seats. Knowledge can be improved with a brief didactic session. (Am J Emerg Med 2002;20:39-42.