The IS help desk function plays a central role in boundary spanning knowledge exchanges within organizations. Help desk employees provide technical support to users in an effort to transfer knowledge and enable users to autonomously apply this knowledge in the future. However, despite their importance, little is known about the factors that affect knowledge application within this context. Adopting interpersonal influence theory, this paper develops a model that examines how dimensions of source credibility - expertise, trustworthiness, and attractiveness impact users’ knowledge application in a help desk environment. The model is tested using a sample of working adults at a large Midwestern hospital who had significant experience requesting help from an IS help desk. Results indicate that all three dimensions of source credibility predict users’ ability to apply the knowledge transferred from a help desk employee. The implications of these results are discussed.