This cross-sectional study sought to determine the prevalence of smoking, readiness to quit, and preferences for smoking cessation treatments among a sample of 236 homeless adults attending 9 sites serving homeless persons (mean age 41.8 years; 73% male). Two thirds (69%) were current smokers, of whom 37% reported readiness to quit smoking within the next 6 months. In bivariate analyses, persons were significantly (P <.05) more likely to be ready to quit if they had tried to quit in the past and if they had social support to quit smoking. Nicotine replacement was the most commonly preferred assistance method (44%), and self-efficacy to quit (10-point scale) was significantly greater if assistance was available (7.3 vs 4.9; P <.001). The findings suggest an urgent need to develop and implement smoking cessation programs for homeless persons.