© 2015 AUR. Rationale and Objectives: Educating medical students on appropriate imaging utilization has been increasingly recognized as important for patient care. The American College of Radiology Appropriateness Criteria (ACR-AC) is designed to support evidence-based imaging examination selection. We sought to assess whether medical students order imaging studies independently, what resources they use for guidance, and whether they use the ACR-AC in clinical practice. A secondary aim was to determine whether increasing familiarity with the ACR-AC could impact student usage. Materials and Methods: We surveyed third year medical students at a single institution on their imaging practices, familiarity with the ACR-AC, and preferences among available resources to guide proper examination selection. The survey was performed in person before a lecture. We also designed a brief intervention to improve familiarity with the ACR-AC and then reassessed students to determine any effect on utilization. Results: The response rate for the initial survey was 103 of 109 (94%) and the response rate for the second survey was 99 of 109 (91%). Our initial survey found students initiated imaging orders independently (74 of 100, 74.8%) and consulted resources to assist in examination selection (50 of 74, 67.6%). Students expressed a preference for non-ACR-AC resources, notably UptoDate via its online mobile application. Few students (8 of 71, 11.3%) were familiar with the ACR-AC. After an intervention to increase familiarity with the ACR-AC, student awareness of the ACR-AC increased to 61 of 74 (82.4%). However, usage among those familiar with the resource remained low, 13 of 61 (21.3%) versus 3 of 8 (37.5%). Conclusions: Use of the ACR-AC was low among third year medical students. After increasing students' familiarity with the ACR-AC, their usage in a clinical setting did not increase. The largest barrier to use may be the lack of a quick, easy to use online mobile application-based interface.