BackgroundRecent insights into substance use cessation suggest that outcomes short of long-term abstinence are clinically meaningful and may offer more realistic incremental goals, particularly for highly vulnerable individuals. With the goal of informing tobacco treatment programs, we examined distinct patterns of cigarette smoking and their association with the ongoing use of other substances in women who experience housing instability. MethodsWe recruited participants from a longitudinal study of women experiencing housing instability. Between June 2017 and January 2019, participants completed six monthly survey interviews regarding social conditions and the use of multiple substances. We examined associations between cigarette smoking intensity, including number of cigarettes smoked per day, heavy smoking, and an increase in number of cigarettes smoked from the previous 30-days, and other substance use in the past 7-days. ResultsOf the 243 participants, 69 % were current smokers and 58 % were daily smokers. Number of cigarettes smoked per day (Adjusted odds ratio [AOR] 1.02, 95 % CI 1.00–1.03), heavy cigarette smoking, compared to none or light smoking (AOR 2.02, 95 % CI 1.46–2.79), and an increase in number of cigarettes smoked from the previous 30-days (AOR 1.06, 95 % CI 1.01–1.12) were all significantly associated with methamphetamine use in the past 7-days. Associations with other substance use were not as strong. ConclusionsIn a sample of unstably housed women, where almost half used multiple substances, methamphetamine use was associated with higher cigarette smoking intensity. Our findings highlight a potential role for integrating tobacco and methamphetamine use treatment to reduce tobacco use among unstably housed women.