The U.S. Preventive Services Task Force recommends that clinicians screen adults for tobacco and alcohol abuse and provide appropriate interventions. This study employed direct observation and interactional analysis of medical visits to investigate factors associated with physician discussion of tobacco and alcohol use with patients. New adult patients were randomly assigned to primary care at a university medical center. Videotapes of the visits were analyzed using the Davis observation code. Regression equations related discussions of substance use (alcohol and other substances), smoking, and health promotion to patient health status, depression, age, education, income, gender, alcohol abuse, and current smoking. Patients reporting better physical health were more likely to have their physicians employ a practice style emphasizing addiction behaviors (p = .0186). Substance use (p = .0117) and health promotion counseling (p = .0130) occurred more frequently with younger patients. Physicians discussed substance use (p = < .0001) and addiction (p < .0001) more often with male patients. Problem drinkers were more likely to have physicians address their substance use (p = .0069) and focus on addiction behaviors (p = .0017). Physicians adopted an addiction-oriented practice style (p < .0001), addressing substance use (p = .0009) and smoking (p < .0001), more often with patients who smoked. Physicians appear more apt to discuss these behavioral risk factors with healthier, younger, male patients who abuse tobacco and alcohol.