In amyotrophic lateral sclerosis (ALS) patients, dysphagia eventually occurs independent of time of onset. We studied dysphagia conditions in the early stage of ALS, principally at the oral phase. Videofluoroscopic and manometric studies were conducted on 11 patients (5 males and 6 females, age range = 47-82 years) who were diagnosed at our Neurology Clinic as having ALS. All patients were able to ingest orally. Swallowing scores on the ALS severity scale were from 10 to 5. In the oral phase of swallowing, abnormal movements of the anterior and/or posterior tongue were recognized in 8 cases. Dysphagia severity tended to be particularly influenced by dysfunction of the posterior tongue. Manometric studies were almost normal in all cases except one. These results suggested that the early stage of dysphagia in ALS was mainly caused by oral dysfunction, and the oral phase disorders began in some cases with a decreased function of bolus transport at the anterior part of the tongue, and in other cases with a deteriorated function of holding the bolus at the posterior part of the tongue. In conclusion, the tongue function of holding the bolus in the oral cavity mainly affects the severity of the early stage of dysphagia in ALS.