Although there are reports of short-term benefits of health literacy curricula for improving health care professionals' communication with patients, no studies have included long-term follow-up. We sought to determine (1) whether a pre-clerkship health literacy training can improve medical students' perceived knowledge and intended behaviors vis-á-vis communication with patients who have low health literacy, (2) the longevity of any such impact at 12 months, and (3) the impact of a follow-up training 1 year later.We conducted pre- and post-training assessments of self-perceived knowledge and perceived and planned behavior following a health literacy training for first-year medical students, with a 12-month follow-up training and repeat pre/post assessment.Among 48 pre-clerkship students, improvement was reported on 10 of 12 items following the Year 1 training. At 12-month follow-up, prior to the Year 2 training, ratings on 8 of 10 items had regressed to baseline levels. Nine of these items again improved significantly after the Year 2 training. Students were asked after both trainings if they felt they had overestimated their understanding of health literacy; significantly more students agreed with this statement following the Year 2 training than the Year 1 training.Among a cohort of pre-clerkship medical students, improvements in perceived knowledge and planned behavior vis-á-vis health literacy training largely did not persist at 12-month follow-up. Efforts to teach medical students about health literacy principles and practices should include a longitudinal or integrated format, rather than a one-time lecture format.