Treatment in ambulatory care settings depends on the patient's behavior to implement the regimen prescribed by the family physician. Behavior modification offers a means for developing behavioral programs that will improve the physician's ability to effectively influence the patient's behavior. This article outlines some of the principles of behavior modification as they can be applied in office settings to diverse behavioral problems. Some specific suggestions are made for identifying behaviors, setting goals, delineating the steps to reach these goals, monitoring progress, and developing treatment contracts that will aid the physician in the management of the behavioral aspects of treatment.