Abstract: Objective: To analyse effects of patient and physician characteristics on questions and advice about smoking in primary care practice and to examine country differences.Methods: We conducted a factorial experiment, employing filmed scenarios in which actors played the role of patients with symptoms of coronary heart disease (CHD) or type 2 diabetes. Versions were filmed with patient–actors of different gender, age, race, and socioeconomic status. The videotapes were presented to primary care physicians in the US, UK and Germany. Physicians were asked whether they would ask questions about smoking or give cessation advice.Results: Female and older CHD patients are less likely to be asked or get advice about smoking in all three countries. Effects of physician attributes are weak and inconsistent. Compared to physicians in the US and the UK, German doctors are least likely to ask questions or give advice.Conclusions: Although all physicians viewed the same cases their questioning and advice giving differed according to patient attributes and country. Due to the experimental design external validity of the study may be limited.Practice implications: Findings have implications for medical education and professional training of physicians as well as for the organization and financing of health care.