The purpose of this project was to describe primary care physician adherence to National Heart, Lung, and Blood Institute (NHLBI) Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, using a measurement tool developed purposefully for the project, and to explore patient characteristics associated with physician assessment and management behaviors. This study sought to add to the body of existing knowledge by analyzing physician clinical behaviors in a more descriptive and systematic manner. The researchers hypothesized that measuring physician behavior for assessing and managing overweight and obesity as a series of steps, as outlined in the NHLBI guidelines, would identify specific gaps in physician action and possibly identify other relationships between patient characteristics and physician behavior. A chart abstraction of 99 randomly selected adult patients with at least one visit to a primary care practice during a 12-month period was completed. Three out of four health center patients were clinically overweight or obese, yet despite high rates of weight status measurement, only 25 percent of overweight and obese patients received such a diagnosis. High levels of weight measurement, including BMI calculations, did not correspond to a weight diagnosis. The majority of patients did not receive any dietary (72 percent) or physical activity (69 percent) management. When dietary management was introduced, patients received either information (68 percent) or a goal (32 percent), and none received a goal with an accompanying plan. In cases where physical activity management was introduced, patients received a goal (52 percent) or information (39 percent). Patients of higher BMIs were more likely to be diagnosed and managed with regard to their weight. Improvements in future weight-related counseling may be found in encouraging physicians' willingness to make weight and weight-related diagnoses. Results from this analysis of assessment highlight that measuring weight status (via BMI) and making a weight-related diagnosis are not the same practice.