CONTEXT: Physicians are regularly confronted with research that is funded or presented by industry. OBJECTIVE: To assess whether physicians discount for conflicts of interest when weighing evidence for prescribing a new drug. DESIGN AND SETTING: Participants were presented with an abstract from a single clinical trial finding positive results for a fictitious new drug. Physicians were randomly assigned one version of a hypothetical scenario, which varied on conflict of interest: 'presenter conflict', 'researcher conflict' and 'no conflict'. PARTICIPANTS: 515 randomly selected Fellows in the American College of Obstetricians and Gynecologists' Collaborative Ambulatory Research Network; 253 surveys (49%) were returned. MAIN OBJECT MEASURES: The self-reported likelihood that physicians would prescribe the new drug as a first-line therapy. RESULTS: Physicians do not significantly discount for conflicts of interest in their self-reported likelihood of prescribing the new drug after reading the single abstract and scenario. However, when asked explicitly to compare conflict and no conflict, 69% report that they would discount for researcher conflict and 57% report that they would discount for presenter conflict. When asked to guess how favourable the results of this study were towards the new drug, compared with the other trials published so far, their perceptions were not significantly influenced by conflict of interest information. CONCLUSION: While physicians believe that they should discount the value of information from conflicted sources, they did not do so in the absence of a direct comparison between two studies. This brings into question the effectiveness of merely disclosing the funding sources of published studies.