A combined retrospective and prospective analysis of infants 60 days of age or less evaluated for fever (greater than or equal to 38.3 degrees C) or history of fever who received chest roentgenogram over a one-year period was performed to determine whether clinical characteristics were predictive of pneumonia. Of the 209 patients studied, 115 were reviewed prospectively and 94 retrospectively. Pneumonia was radiographically diagnosed in 16 patients. Individual clinical factors were not found to be highly predictive of pneumonia. However, infants with the following nine factors did not have pneumonia; illness in the summer months; absence of cough, dyspnea, and respiratory distress (grunting/flaring/retracting); respiratory rate less than 60; absence of rales and decreased breath sounds; presence of normal color; and white blood cell count less than 19,000/mm3. We recommend that these clinical characteristics be utilized to determine whether chest roentgenogram is warranted in the young infant evaluated for fever.