The role of the chest roentgenogram in febrile neutropenic patients. In a retrospective review of patients with neutropenia and fever, we sought to determine how often roentgenograms detected pulmonary disease, especially pneumonia, not suggested by signs and symptoms. Further, we sought to determine how often therapy was changed as a result of roentgenographic findings. Overall, 41 (22%) of 187 chest roentgenograms obtained during initial febrile episodes, recurrent fevers, or persistent fevers were abnormal. While most patients had signs and symptoms suggesting the presence of pulmonary disease, 17% had roentgenographic abnormalities detected in the absence of such findings. During initial febrile episodes, therapy was not changed in response to findings on the chest roentgenogram. However, during episodes of persistent or recurrent fever, findings on chest roentgenograms led to changes in therapy in eight (61%) of 13 episodes of which six (40%) resulted in clinical improvement. Chest roentgenograms were therefore found to be an important diagnostic tool in evaluating recurrent or persistent fever in the neutropenic patient but of little use during initial febrile episodes. 