 The NIH-sponsored M Health Training Institutes, MHTIs, are designed to bring together researchers from various disciplines to work on projects related to mobile health. This study used longitudinal social network analysis to investigate the effectiveness of the MHTIs at fostering interdisciplinary communication. It found that conversations between scholars from different disciplines were just as likely as those within disciplines to form or persist over time, indicating that the MHTIs successfully promoted interdisciplinary collaboration. Additionally, the presence of team and gender homophily effects in some years suggests that scholars tend to communicate with members of their own team or gender. This article was authored by Eric Ho, Min Jong-jong, Min Ho Lee, and others.