The 2000 United States Public Health Service (USPHS) clinical practice guideline, "Treating Tobacco Use and Dependence," recommends systems interventions to integrate the treatment of tobacco into routine health care. The Tobacco Control Initiative employed a systems approach to integrate evidence-based treatment for tobacco use into patient care practices in Louisiana's safety net health care system. The purpose of this study was to assess changes in awareness and implementation of the USPHS clinical practice guideline. Surveys were administered to a purposive sample of hospital personnel from key departments in the Louisiana State University system of public hospitals in 2003 (n = 24) and 2007 (n = 44). Perceptions of implementation success improved for 50 of 59 distinct survey items. Rasch scaling was used to assess overall (scaled) change and showed substantial improvement from 2003 to 2007 (P < 0.001). Survey items also were grouped into 6 logical key concept sets. Improvement occurred in perceptions for all 6 key concepts; however, not uniformly. Results of the 2003 and 2007 surveys illustrate the potential effectiveness of using a systems approach to integrate the assessment and treatment of tobacco use into routine care practices in a public health care delivery system that serves medically vulnerable populations.