Two hundred routine chest x-rays were evaluated to determine their value in the management of critically ill patients in a Medical ICU (MICU). Seventy-four x-rays (37%) were of suboptimal value or were delivered to the MICU too late for inclusion on morning rounds. Of the remaining 126 films, 54 (43%) showed worsening of a known, or development of a new, cardiopulmonary abnormality, or an unexpected misplacement of an invasive device. On the basis of these findings, routine daily chest radiographs were judged to be valuable in identifying abnormalities in critically ill patients. However, the system for providing this service was only 63% efficient, and improvement must be sought in this regard.