Neurofeedback therapy is a method allowing for a change of the bioelectrical functioning of the brain. By using the mechanism of instrumental conditioning, it changes the amplitude of selected brain waves. It allows for suppressing the waves of a too high amplitude and amplify the waves of a too low amplitude, with correlates with psychological and neurological disorders. In the described cases primarily a global training was applied, than it was changed for a specific one, influencing the parts of the brain critical for the given disorder. The first case is a male aged 21 with an organic disorder of the CNS. In the childhood he was suspected of microcephaly. In that period a little retardation of his psychomotor development was observed. In the neurological examination signs of a vegetative dysregulation were found without focal dysfunctions of the CNS. Based on the interview, neuroimaging and psychological assessment he was diagnosed organic personality disorders. The therapy significantly improved the functioning of attention, and visual memory, increased the patients` self-esteem, and reduced anxiety. The second case a male aged 52 male suffering from cyclothymia. In the clinical picture sleep disorders were dominant, accompanied by deficits of memory and attention. The therapy reduced the anxiety level, improved his sleep, and enhanced cognitive functioning. The third case is a female aged 29, suffering from paranoid schizophrenia. The therapy significantly improved the functioning of attention and visual working memory. The cognitive changes reduced her autistic symptoms allowing for better social contacts, and reduced anxiety.