The 9th observation of esophageal intramural diverticulosis is reported. The findings are compared with those of former publications. Clinically dysphagia is a leading symptom. Suction biopsy proved diverticulosis being the correct interpretation for radiological findings. The etiology is discussed. The change between symptom-free intervals with diverticulosis only and episods of dysphagia by secondary inflammation (reflux esophagitis, moniliasis, stenosis) stresses the importance of such secondary complications. These inflammations can hide the real diagnosis for a long time. The radiological findings are the key for diagnosis, however, they can be very small for years. During this period a diagnosis can only be achieved by knowledge of the disease and the skilful search for early symptoms.