Purpose:This study aims to identify the beliefs, attitudes, and opinions of nursing professionals associated with tobacco smoking and its prohibition in a psychiatric hospital in Brazil.Methods:Using a cross-sectional epidemiologic study, a total of 73 nursing professionals in a smoke-free psychiatric hospital were interviewed. The Varimax Rotation and the Fisher's exact test at a 5% significance level were used to analyze the responses.Findings:Most nursing professionals reported observations of patients becoming calmer after smoking (n = 59, 80.8%) and tobacco withdrawal worsening patients' mental health symptoms, suggesting agreement among professionals that some psychiatric patients need to smoke tobacco. Most respondents stated that patients with mental health disorders have more difficulty with smoking cessation (79.4%) and are less interested in quitting smoking than those without disorders (95.9%). While one-third mentioned having used cigarettes as a reward or bribe, the majority (83.6%) was in favor of continuing the smoking ban, with more support observed from those working on a night shift and those who worked in the public psychiatric wards. Over 71% noted improvements in their health after the smoking ban.Conclusion:The nursing professionals were surprised by the effectiveness of the smoking ban and highlighted the improvement in the hospital environment after its implementation.Clinical relevance:As trusted healthcare professionals, nurses are essential in the fight against smoking and can contribute to awareness promotion, supporting patients during nicotine withdrawal, and decision-making processes for health policies.