The Zenker posterior pharyngoesophageal diverticulum results from the posterior herniation of the hypopharyngeal intima near its junction with esophagus. To its occurrence contribute more factors exerted at the level of Leimer's triangle. It has a slow progressive evolution and may thus vary in size from a beam to an apple or even the head of a foetus, determining compressions against the esophagus. The clinical symptoms depend on the evolutive stage. The radiological semiology of the evolutive stages of Zenker diverticulum is discussed and a casuistics with its various radiological aspects is presented.