Fifteen patients with oculopharyngeal muscular dystrophy underwent cricopharyngeal myotomy for palliation of dysphagia. The aim of this work was to assess the effectiveness of this operation by using a radionuclide pharyngeal emptying study as a new quantitative method in addition to clinical and manometric evaluation. Radionuclide study was performed with the patient in both the upright and the supine positions after ingestion of 15 ml of water labeled with sulfur colloid 99mTc. Computerized data were acquired at 0.5 second intervals for 15 minutes and a pharyngeal time-activity curve was generated. Four quantitative parameters were evaluated: the time for pharyngeal clearance of 25%, 50%, and 75% of the ingested radioactive water and the pharyngeal stasis at 15 minutes. Manometric studies were also performed before and after cricopharyngeal myotomy. The pharyngeal clearance of 25%, 50%, and 75% of the water and pharyngeal stasis at 15 minutes were all improved by cricopharyngeal myotomy, decreasing from 1.2 to 0.9 second (p less than 0.04), 4.2 to 2 seconds (p less than 0.005), 15 to 7 seconds (p less than 0.02), and 10.3% to 6% (p less than 0.01), respectively. Both pharyngoesophageal and tracheobronchial symptoms were also significantly improved by cricopharyngeal myotomy. Manometric evaluation showed a decrease of the upper esophageal sphincter closing pressure from 60.1 mm Hg before to 28.2 mm Hg after the operation (p less than 0.001), and the resting pressure decreased from 34.4 to 15.7 mm Hg (p less than 0.0005). Cricopharyngeal myotomy significantly improves both symptoms and pharyngeal emptying in patients with oculopharyngeal muscular dystrophy.