BACKGROUND: The rates of cigarette smoking among patients with schizophrenia are two to four times the rates observed in the community. Spirituality and religiousness have been shown to be associated with lower smoking rates in the general population. AIMS: This study assessed the role of religion in cigarette smoking among patients with schizophrenia or schizo-affective disorder. METHODS: Some 115 stabilized outpatients from Geneva's public psychiatric facilities were included. Interviews were conducted to investigate spiritual and religious beliefs, religious practices and religious coping. Cigarette smoking was assessed through interviews and medical records. RESULTS: Some 58% of patients were smokers. Two-thirds of the total sample considered spirituality as very important or essential in their every day life. Religiosity was negatively associated with tobacco use: there were more current smokers without religious affiliation than non-smokers (p < 0.05). For non-smokers, the support of their faith community was significantly more important and they reported more frequent group religious practices than smokers ( p < 0.05). This relation persisted after controlling for demographic confounders (gender, age, ethnicity, education, civil status). CONCLUSION: In patients with schizophrenia, religion and spirituality seem to be related to smoking behaviour. Similar results were previously found in the general population. These results underscore the need for a systematic exploration of religious issues in the care of smokers with schizophrenia.