Background: The increasing consumption of dietary supplements (DS) has drawn the attention of regulatory agencies, researchers and healthcare professionals. The US Food and Drug Administration (FDA) does not require premarketing assessment of DS considering them safe unless proven otherwise. However, the reporting rate of DS adverse events (DS-AE) is low. Objective: To describe pharmacists’ attitudes and knowledge of DS and DS information resources, and to determine the importance of selected attributes in pharmacists’ decisions to report a DS-AE. Methods: A convenience sample of practicing pharmacists in Virginia was surveyed using a web-based self-administered questionnaire. A conjoint analysis exercise was developed using several scenarios based on a set of five attributes: patient’s age, initiation of DS, last modification in drug therapy, evidence supporting the AE, and outcome of the AE. Participants were asked to indicate their decision to report the AE in each scenario to prescriber, drug manufacturer, DS manufacturer and FDA on a 6-point ordered scale. Participants’ attitude, knowledge of DS, demographic information, and DS information resources were also requested. Linear regression models were used to determine the relative importance of the profile attributes on a pharmacist’s decision to report the AE. The effects of other characteristics on the importance of the attributes were assessed. Results: Participants’ overall attitudes were relatively positive for the clinical use of DS but negative for safe of DS. Formal training on DS was associated with better knowledge of DS regulation. The average knowledge score of DS identification was relatively good but was low for DS regulation. Lexi-Comp® was the most widely used and available information resource and the Natural Medicines Comprehensive Database was the most useful once. The most important attribute that a pharmacist considered in the decision to report a DS-AE to DS manufacturer, drug manufacturer and FDA was the outcome of the AE followed by the evidence supporting the AE. Ranking of these two factors was the reversed in reporting to prescriber. Conclusions: Outcome and evidence of the AE are the most important factors participants considered when reporting. Other characteristics do not have an impact on the relative importance of the attributes.