A group of 185 patients with brain atrophy found in CT is presented. The purpose of the study was to call attention to the the significance, frequency and clinical signs of brain atrophy. All patients were divided into two groups: 78 cases with secondary brain atrophy associated with other diseases of central nervous system and 107 cases of "primary" brain atrophy. The last one was an only finding without any other pathological lesions in the brain. Depending on the localisation, three groups of brain atrophy were isolated: generalized, subcortical and cortical. The clinical picture was analysed in the group of "primary" brain atrophy. In the studied group the most frequent cause of hospitalisation were epileptic seizures, the next one: headache, one-side hemiparesis or hemihypaesthesia, dizziness and incoordination. Neurological examination showed that one-side signs were observed very often in generalized brain atrophy. In the group of patients with cortical brain atrophy most patients were without any neurological signs. The analysis of the relationship between the clinical examination and "primary" brain atrophy found in CT, showed lack of characteristic, typical signs, which could be connected with brain atrophy. The problem of difficulty in the diagnosis of brain atrophy is stressed aesthesia. The definition and the significance of brain atrophy should be verified in diagnosis and the conclusions after finding brain atrophy have to be very careful.