Ketamine is a rapid-acting anaesthetic agent which has been used for over 40 years. It is an antagonist of N-methyl-D-aspartate (NMDA) receptors and agonist of mu and sigma opiate receptors. Ketamine acts through inhibition of sensory parts in the brain and Stimulation of the limbic system and optic thalamus. The most common psychiatric disorders observed after the use of ketamine are: psychomotor agitation, hallucinations, status of stupor, consciousness disorders. There are observed cases of non-medical use of ketamine since the sixties of the 20(th) century. The authors describe the case of a 52 year old man who has been addicted to ketamine for 15 years. The patient was admitted to hospital to observe and treat the withdrawal syndrome as an effect of abrupt discontinuation of a chronically abused substance. On the ground of medical examinations, standard tests, anamnesis and hospital observation, ketamine dependence syndrome of a person with personality disorders was recognized. There was no somatic symptoms of withdrawal syndrome observed. The patient complained of sleep disorders and anxiety. Diazepam, carbamazepine and vitamins was used during treatment. The patient was motivated to stop using ketamine. This case and the described symptoms were compared with others articles.