Rumination syndrome is one of the functional gastroduodenal disorders. Effortless and repetitive regurgitation of recently ingested food from the stomach to the oral cavity followed by rechewing and reswallowing or spitting are the characteristic clinical features. This disorder is believed to be uncommon, but many patients with this disorder are overlooked by their physicians. Rumination might be caused by a reversal of the gastric contents through the esophagogastric junction, which is initiated by an increase in intragastric pressure. The characteristic symptoms are sufficient for the diagnosis of rumination syndrome. Postprandial high resolution esophageal impedance manometry can detect gastric pressurization exceeding 30 mmHg associated with the return of ingested material into the proximal esophagus, which is a pathognomonic finding of rumination syndrome. An extensive explanation of the condition and the underlying mechanism is the first step of the treatment of rumination syndrome. Behavioral therapy through diaphragmatic breathing is the mainstay of treatment. Further studies on the long term effects of biofeedback therapy as well as a proper strategy for refractory rumination syndrome are needed.