Understanding smoking behaviors in adults with diabetes is thus essential to efforts to improve population health. This is particularly true in areas where diabetes prevalence is high, such as the United States–Mexico border region. In 2001–2002, 1.2 of 7.5 million adults in the region (15.7%) had diabetes (9). Diabetes prevalence in U.S. and Mexico border populations was substantially higher than national estimates from either country (10, 11). This study examined smoking behaviors in the border popula- tion with diabetes as a whole as well as differences among Hispanics with dia- betes living on either side of the border. The investigation used data from the U.S.–Mexico Border Diabetes Prevention and Control Project. The project has taken the unique view of the border re- gion as a single epidemiologic unit and was undertaken to coordinate efforts to decrease the impact of diabetes across the region.