In the course of six years from 1991–1996 the authors treated 17 patients with the diagnosis of Dandy-Walker complex. They adhere to the anatomical-radiological definition and three-grade classi- fication according to MR (1. persisting Blake’s diverticulum, 2. Dandy-Walker variant, 3. Dandy-Wal- ker malformation). Six patients were treated by shunt on account of supratentorial hydrocephalus, five patients with facultative ventilation symptoms and/or symptoms from the posterior cranial fossa were continuously monitored for 48 hours. Two of them were indicated for a shunt operation (once cystope- ritoneal and once ventriculoperitoneal), three patients, along with six with non-specific or no clinical symptoms were indicated for observation. The authors demonstrate on the small group of patients the clinical variety of the group with a common embryological origin. In a review they demonstrate different approaches to different grades of affliction, discuss indication and therapeutic limits and contemporary possibilities of alternative examination. They mention also the first (in the CR) results of continuous and parallel monitoring of the cerebrospinal fluid pressure. In the conclusion they mention the limited possibilities of surgical treatment of patients with an inborn defect. The article is loosely connected with previous three parts: malformations of the hind brain 1. A review of the systematics and etiological theories, 2. Syringomyelia, review, and 3. Chiari’s malformation in adults. Clinical picture and surgical treatment.

        Key words: Dandy-Walker complex, hydrocephalus, mental retardation, posterior cranial fossa, cysto- peritoneal shunt