In the United States, tobacco treatment specialists are professionals from a variety of backgrounds trained to deliver moderate to intensive evidence-based tobacco treatment in a variety of settings across the country. This paper reports the results of a study that examined the extent to which specialists participating in a larger study adhered to clinical practice guidelines for tobacco dependence using standardized patient assessments. A total of 64 tobacco treatment specialists completed a survey and two audiotaped standardized patient interviews. Overall, 41% and 31% of tobacco treatment specialists demonstrated 80% or more of session content and interviewing skills assessed, respectively, when required to demonstrate the skill in both standardized patient interactions. These rates increased to 85% and 56%, respectively, when using the less stringent criteria of demonstrating the skill in at least one of the two standardized patient interactions. Tobacco treatment specialists who had attended a greater number of types of tobacco treatment training exhibited both greater coverage of session content (p<.06) and greater interviewing skills (p<.02). Those who had achieved certification as a tobacco treatment specialist exhibited greater coverage of session content (p<.02), and those perceiving more positive support from their agency for their services exhibited greater interviewing skills (p=.02). Although the tobacco treatment specialists evaluated appear to have the necessary skills to deliver guideline-based intervention, they demonstrated only moderate adherence to the guidelines when expected to do so consistently across multiple assessments. Findings suggest specific components of tobacco treatment and interviewing skills that would benefit from strengthening through training and support.