Carbon monoxide (CO) is a highly toxic, odorless, nonirritating gas. The most common cause of its exposure are faulty combustion heating systems and fires. CO competes with oxygen in the blood, binding to haemoglobin in place of it (the affinity of CO to haemoglobin is approximately 200 times greater than that of oxygen). Secondary hypoxia leads to damage of multiple organs especially those with high oxygen utilization such as the central nervous system. A case of a 26-year-old woman with prolonged deep cognitive impairment, which occurred after an accidental carbon monoxide intoxication, is presented. A course of over 2-year neuropsychological rehabilitation of the patient is thoroughly described by the authors and its positive effects are emphasized. In spite of all prophylactic measures carbon monoxide poisoning still remains a significant clinical issue. CO intoxication may produce a wide spectrum of neurological, emotional and cognitive disorders. Neuropsychological rehabilitation is an effective method of treatment of cognitive impairment after carbon monoxide intoxication. Positive effects of a systematic rehabilitation are observed even several years after poisoning.