Several studies indicate that schizophrenic patients smoke more than normal subjects or non-schizophrenic psychiatric patients. It has been suggested that the excessive smoking behaviour of the schizophrenic patient may be connected with stress, hospitalization or the hopelessness and the monotony of his existence. There could be more to it. Nicotine stimulates the dopaminergic system and this system is also affected in schizophrenic patients. The present article summarizes research findings that indicate that the connection between schizophrenia and nicotine could have a biological origin.