This study in a Spanish hospital replicated two US studies suggesting that schizophrenia is associated with smoking when compared with other severe mental illnesses. Neither antipsychotics nor institutionalism could explain this relationship. Seventy of the 100 schizophrenic and 53 of the 100 non-schizophrenic inpatients were current smokers. After correcting for confounding factors, schizophrenia increased the risk of smoking by 2- to 3-fold. Heavy smoking was not associated with schizophrenia.