Objectives: To describe the issues encountered during the implementation of an indoor smoking ban in prison and its effects on self-reported tobacco use, perceived exposure to secondhand smoke (SHS) and perceived health status of inmates in Quebec's provincial correctional facilities. Methods: Quantitative data were obtained from 113 inmates in three provincial correctional facilities in the province of Quebec, Canada. Qualitative data were obtained from 52 inmates and 27 staff members. Participants were recruited through a self-selection process. Particular efforts were made to enrol proportions of men, women, smokers and non-smokers similar to those generally found among correctional populations. Results: Despite the indoor smoking ban, 93% of inmates who declared themselves smokers reported using tobacco products inside the correctional facilities and 48% did not report any reduction in their tobacco use. Only 46% of smokers declared having been caught smoking inside the facility, and more than half of them (58%) reported no disciplinary consequences to their smoking. A majority of inmates incarcerated before the implementation of the ban (66%) did not perceive a reduction of their exposure to SHS following the indoor ban. Enforcement issues were encountered during the implementation of the indoor ban, notably because of the amendment made to the original regulation (total smoking ban) and tolerance from smokers in the staff towards indoor smoking. They were also related to perceptions that banning indoor smoking is complex and poses management problems. Conclusion: This study's findings emphasize the importance of considering organizational and environmental factors when planning the implementation of an indoor smoking ban in correctional facilities.