In the gastroenterological diagnostic armamentarium, dysphagia is considered as an important symptom for diseases of the esophagus. Concerning the history of illness, symptoms such as retrosternal pain and heartburn are often associated with gastroesophageal reflux disease. Morphological changes of the mucosa can be diagnosed by flexible endoscopy and radiographic examinations. Investigation with 24-h pH monitoring, manometry, and pharmacological tests is necessary for the diagnosis of functional disorders. Additionally, dysphagia can be associated with multiple internal diseases, including muscular diseases such as dermatomyositis, progressive systemic sclerosis, as well as lupus erythematosus. Difficulties in swallowing associated with hypo- and hyperthyroidism can also be interpreted as muscular lesions. Metabolic disorders such as alcoholism, and diabetes mellitus can be the cause of dysphagia. Increasing importance in the differential diagnosis of dysphagia is attached to infections of the upper GI tract. Especially in immunocompromised patients, infections of Candida albicans, mycobacterias, herpes, varicella zoster, and cytomegaloviruses can produce dysphagia and odynophagia. The differential diagnosis of the "angina-like chest pain" has to differentiate between cardiac disease and a noncardiac genesis. Therefore, besides the cardiac diagnostic investigation, endoscopy, radiography, and manometry are often indicated.