The following report illustrates a rare case of dysphagia caused by secondary adrenal insufficiency in a patient with isolated ACTH deficiency. A 76-year-old man with progressive appetite loss, weight loss and general fatigue was hospitalized due to dehydration, aspiration pneumonia and hypoglycemia. He was unable to stand and walk by himself. His serum cortisol and ACTH levels were both low. An endocrinological examination resulted in a diagnosis of isolated ACTH deficiency. Following the administration of 15mg of glucocorticoids daily, his symptoms diminished without dysphagia. Furthermore, we investigated his swallowing function using a videofluoroscopic examination of swallowing (VF). The VF showed an impaired laryngeal movement as well as an upper esophageal opening and severe aspiration without a delay in his swallowing reflex. Oral intake was judged to be impossible, but his swallowing function gradually improved and he was able to resume eating all of his meals 2 months after treatment. Dysphagia is not a common symptom in ACTH deficient patients but a few similar cases have been reported. The swallowing function of the patients in these cases was not evaluated in detail, so we evaluated this case according to the results of the VF and the patient's process of recovery. Careful monitoring of swallowing function and appropriate treatment for both dysphagia and adrenocortical failure are required for the recovery of such patients. In conclusion, practitioners should be wary of isolated ACTH deficiency in elderly patients with progressive weight loss and dysphagia.