Background: People with a mental illness experience a higher burden of smoking-related disease. Smoke-free policies in mental health facilities provide an opportunity to reduce smoking-related harms for patients and staff alike. Limited evidence regarding the effect of such policies on preventing smoking in mental health facilities has been reported. The aims of this study are to describe the extent of smoking and the provision of nicotine replacement therapy (NRT) to patients in a mental health facility with a smoke-free policy.Methods: Cross-sectional studies of smoking (cigarette butt count and observed smoking) and nicotine dependence treatment (patient record audit) were undertaken over 9 consecutive weekdays in one mental health facility in Australia. A smoke-free policy incorporating a total smoking ban and guidelines for treating nicotine dependence among patients was implemented in the facility 4 years prior to the study.Results: Two thousand one hundred and thirty seven cigarette butts were collected and 152 occasions of people smoking were observed. Staff members were observed to enforce the policy on 66% of occasions. Use of NRT was recorded for 53% of patients who were smokers.Conclusion: Implementation of the smoke-free policy was less than optimal and as a consequence ineffective in eliminating smoking and in optimising the provision of NRT. Additional strategies to improve the provision of nicotine dependence treatment to patients and the monitoring of adherence are needed to ensure the intended benefits of smoke-free policies are realised.