Smoking prevalence among homeless persons is approximately 70%, yet little is known about tobacco use patterns or smoking cessation practices in this population. We assessed smoking attitudes and behaviors, psychosocial and environmental influences on smoking, barriers to and interest in quitting, and preferred methods for cessation among some homeless smokers. Six 90-min focus groups of current smokers (N = 62) were conducted at homeless service facilities. Participants had a mean age of 41.5 years (SD = 9.3), were predominantly male (69.4%) and African American (59%), and smoked an average of 18.3 cigarettes/day. Although most reported that they were motivated to quit, a number of barriers to quitting were identified. Participants reported that the pervasiveness and social acceptance of tobacco use in homeless settings contributed to smoking more cigarettes per day, adopting alternative smoking behaviors such as smoking cigarette butts and making their own cigarettes, and experiencing difficulty in quitting. High levels of boredom and stress also were cited as reasons for continued smoking. Smoking frequently occurred in combination with alcohol or illicit drug use or to achieve a substitute "high." Most participants (76%) reported that they planned to quit smoking in the next 6 months. Many were interested in using pharmacotherapy in combination with behavioral treatments. Results suggest that, although motivated to quit smoking, homeless smokers are faced with unique social and environmental barriers that make quitting more difficult. Interventions must be flexible and innovative to address the unique needs of homeless smokers. Smoking restrictions at homeless service facilities and funding for smoking cessation assistance in this underserved population may help to reduce prevalence.