Zenker's diverticulum (ZD) is a rare pathology, with a prevalence of between 0.01% and 0.11%. Definitive diagnosis of ZD can be accomplished by contrast radiographic examination (barium oesophagogram, BE); oesophageal manometry (ME) is recommended mainly for those patients suffering from dysphagia and/or gastro-oesophageal reflux. The aims of the present study were to assess whether oropharyngo-oesophageal scintigraphy (OPES) is able (a) to visualise ZD and (2) to demonstrate the corresponding alteration in the swallowing phases. We studied 16 patients (nine male, seven female, mean age 67.4 years), and 17 healthy volunteers (ten male, seven female, mean age 53 years) as a control group. All the patients underwent ME, BE and OPES. Nine patients underwent surgery and six of them were re-evaluated after 6 months. We administered 10 ml of water with 37 MBq of technetium-99m colloid through a straw, acquiring 480 sequential images (0.125 s/frame for a total of 60 s) with the patient standing in front of the gamma camera in the 80 degrees right anterior oblique position. Two static images were performed at the end of the dynamic phase, before and after ingestion of 100 ml of unlabelled water to evaluate the presence of inflammation (persistence of radioactivity in the diverticulum or oesophagus). Study of the sequential scintigraphic images and time-activity curves permitted both qualitative (diverticulum visualisation, multiple deglutitions, reflux, presence of inflammation) and quantitative analyses [oral, pharyngeal and oesophageal transit times and retention indexes, tracheal aspiration percentage] of swallowing disorders. OPES showed a good correlation with the results of other diagnostic techniques usually performed in patients with this pathology, and especially with ME in the evaluation of oropharyngeal phase disorders. Furthermore, OPES is a sensitive and simple technique that is well tolerated and entails a low irradiation dose for patients.