The objectives were to determine the rate of physician/patient discussions regarding diet, exercise, and smoking and to assess the effect of such discussions on behavior change. In a telephone survey of Connecticut adults, respondents who had a routine checkup in the past year (n = 433) were asked whether their physicians had asked them about their dietary habits, exercise, or smoking, and about any efforts to modify these behaviors during the preceding year. Diet was addressed with 50% of the subjects, exercise with 56%, and smoking status with 77%. Respondents who were asked about their diet were more likely to have changed their fat or fiber intake in the past year than those not asked (64 vs. 48%, P = 0.002) and were somewhat more likely to have lost weight (46 vs. 37%; P = 0.061); the differences were even greater among 94 overweight subjects (64 vs. 47%; P = 0.099). No behavior change was associated with discussions of exercise or smoking. Physicians have the potential to impact health behaviors, especially those related to diet, through simple discussions during routine checkups, but only about half are using this opportunity. Copyright 2000 American Health Foundation and Academic Press.