The findings support previous studies that have shown possession fines can reduce youth tobacco use. The findings are also consistent with previous research that has suggested younger children may be more susceptible to the influence of this policy tool, perhaps because they are more accepting of adult sanctions and less likely to have developed a smoking addiction. Of those who were given a ticket for a PUP law violation, 35 (39 percent) reported not smoking during the first year. Students in the 7th grade were more likely to have quit smoking (84 percent) than those in 8th grade (35 percent), 9th grade (32 percent), or 10th grade (21 percent). For 2 followup years, 45 percent and 41 percent reported not smoking. More knowledge about processes that might account for changes in tobacco use among PUP law violators is critical for the development of successful community and policy responses to youth tobacco use. The current study is part of a larger longitudinal project that is examining ecological contexts of youth smoking. The study used data collected from these towns in the spring of 2001, 2002, and 2003. In 2001, which was the first year of data collection, 10,745 students from 41 middle and high schools in northern and central Illinois completed a survey. Of these students, 52 percent were female and 48 percent were male. As part of the larger study, students completed a survey in their school during the months of March, April, and May of 2001, 2002, and 2003. The survey was administered to students in grades 7 to 10 during 2001, grades 7 to 11 in 2002, and grades 7 to 12 in 2003. A total of 10,745 eligible participants completed the survey (54 percent). Exclusions brought the final sample to 10,435. 15 references