A prospective study of chest radiographic examinations in a respiratory intensive care unit was conducted to determine the diagnostic and therapeutic efficacy of such examinations. Analysis of data from 1,354 x-ray films from 167 patients revealed a 34.5 percent incidence of new (or increased) abnormalities, or tube or catheter malposition. Changes in diagnostic approach or therapeutic measures, excluding catheter position adjustments, occurred after 28.5 percent of the examinations. Radiographic yield was higher when a change in clinical condition prompted the radiographic examination than when the examination was a routine morning study. Changes in the approach to patient management were also more likely (42.7 percent) following examinations that were prompted by a change in a patient's clinical status. Less than 6 percent of the radiographic films taken post-procedure demonstrated abnormalities potentially related to the procedure. We conclude that, in a respiratory intensive care unit: routine morning radiographic examination frequently demonstrates unexpected or changing abnormalities, many of which prompt changes in diagnosis or management radiographic evaluation of a change in a patient's clinical condition has a higher yield than routine examinations; and post-procedure radiographic examination uncommonly demonstrates complications related to the procedure, but frequently demonstrates abnormalities of tube or catheter placement.