Though exempted from national bans of tobacco smoking in hospitals, some psychiatric facilities have voluntarily gone 100% smoke free with little reported difficulty in clinical management. The impact of smoking restrictions on psychiatric patients' thoughts about quitting smoking, however, is not known. This study investigates changes in thoughts about quitting smoking for patients hospitalized in a smoke-free psychiatric inpatient facility. Participants were 100 smokers recruited from a university-based adult inpatient psychiatry unit. The present study focused on participants' reported desire to quit smoking, their expectancy of success and anticipated difficulty with quitting, and their smoking abstinence goal. Assessments were conducted at hospital intake and shortly before hospital discharge. Follow-up assessments were conducted by phone at 1 week, 1 month, and 3 months post-hospitalization to measure smoking behavior. Although no cessation treatment was provided in this observational study, from admission to discharge, participants reported an increased expectancy of success with quitting and a decreased expectancy of difficulty with staying quit. They also were more likely to endorse a smoking-related goal. Psychiatric diagnosis was not related to thoughts about abstinence. Furthermore, participants' thoughts about abstinence at discharge were significantly related to their subsequent smoking behavior. Hospitalization in a smoke-free environment is associated with increases in patients' expectancies about quitting and staying smoke free.