The correlation of Waters view radiographs and A-mode ultrasound for diagnosing sinusitis was evaluated in 75 subjects with allergic rhinitis who presented with signs and symptoms suggesting sinus disease. All patients had Waters view radiographs, which were read by a radiologist (E. G.) who was not provided with historical information. Ultrasound tracings were obtained by registered nurses who were trained to perform this procedure. Tracings were interpreted by two representatives of American Electromedics Corporation, the manufacturer of the Echosine ultrasound machine used in this study. Most common symptoms among the patients were cough and rhinorrhea. The complaint of headache correlated negatively (p = 0.001) with an abnormal radiograph, whereas physical findings of copious and purulent rhinorrhea correlated positively (p = 0.05 and 0.001, respectively). Middle ear abnormalities on examination and tympanometry were more common in those with abnormal radiographs, p less than 0.05 and p less than 0.01, respectively. If the radiograph is considered to be a "gold standard," sensitivity of ultrasound varied from 44% to 58% and specificity from 55% to 61%, dependent on which criteria are applied to the radiograph to consider it normal. A-mode ultrasound is not sufficiently comparable to radiography to be used as its substitute for diagnosing sinus disease.