['We explored comfort levels of third-year medical (M3) students through two health behavior counseling (HBC) interactions with Standardized Patient Instructors (SPIs) in tobacco cessation (TCC) and nutrition and physical activity (NPA).', 'Nearly 200 M3s participated in two SPI HBC interactions; including a role-play interview and subsequent feedback session on performance. Students completed a 5-point Likert scale evaluation measuring pre- and post-comfort level on two HBC sessions.', "Both interactions resulted in statistically significant increases in student's pre- and post-interaction comfort levels. A paired-sample t-test revealed a mean increase of 0.91 for TCC (t = 14.01, df = 197, p<0.001), and a mean increase of 0.69 for NPA (t = 12.65, df = 198, p<0.001)."] Are standardized Patient Instructor ( SPI ) interactions a viable way to teach medical students about health behavior counseling?