Currently, stuttering studies focused on central nervous system pathology are one of those which develop most dynamically. Stutterers display various disorders within the anatomy of centres which control realization and abnormal lateralization of language functions, as well as functional disorders. Abundant research has proved that stutterers display disturbed functional brain asym- metry. The left hemisphere speech representation in a stutterer’s brain is marked less clearly than in the case of fluent speakers. Speech fluency comes from realizing the motor plan, which is abnor- mally synchronised in a stutterer’s brain. Similarly, stuttering people display incorrect cooperation between the language program and its motor performance. Dysfunctions are observed not only in the expressive speech areas, but also in the hearing centres, whose proper functioning is vital for normal course of speech. Research has showed the disturbed auditory feedback control of speech among stutterers, which is thought to be caused by anatomical and functional abnormalities within the brain hearing area. Results of studies concerning stutterers’ brain structure and functioning point to numerous abnormalities observed in the whole functional system of speech. Importantly, these functional differences occur among stutterers during actual speech and even when speaking is only visualized in the stutterer’s mind.