Gastric and esophageal motility disorders are a frequent cause of symptoms in the upper gastrointestinal tract. Impaired esophageal motoric function leads to impaired bolus transport, gastroesophageal reflux or reduced esophageal clearance, which in turn lead to dysphagia, chest pain, heart burn and/or regurgitation. Knowledge of the relevant pathophysiological mechanisms and an understanding of the merits and limitations of the various diagnostic procedures are essential for an efficient and targeted diagnostic approach to functional gastrointestinal disorders. Gastric function is a combination of gastric structure and motility as well as multiple neurohumoral feedback mechanisms, which themselves influence gastric motility and emptying. Impaired gastric function can lead to delayed gastric emptying, i.e. gastroparesis, which can cause early satiety, nausea/vomiting and, in extreme cases, weight loss. Currently, gastric function as a whole can not be assessed due to the lack of a global function test; however, a variety of diagnostic tools are available to assess partial aspects such as gastric emptying or accommodation. In addition to gastric scintigraphy, which currently represents the gold standard for the evaluation of gastric motility, the most important other methods, their limitations and their range of application are discussed.