OBJECTIVE: Over the last 15 years pharmacoeconomics research has grown rapidly, but economic evaluations seem to have little impact on decision-making. We conducted semi-structured interviews with hospital pharmacists in a French region to determine the barriers that prevent their use in hospital formulary decision-making. METHODS: We developed an interview schedule based on a literature review and three pilot interviews. We interviewed pharmacists in short stay hospitals with more than 100 beds. Thirteen public hospitals (PH) and six private clinics (PC) in the Rhone-Alpes region, in France, were randomly selected. Interview transcripts were coded independently by two researchers. We compared the six PC, financed on a fee-for-service basis, with the 13 PH, financed on a global budget basis, by multiple correspondence analysis. RESULTS: In all hospitals economic evaluations have little impact on formulary decision-making. The barriers that prevent their use are: (1) decision-makers do not have enough time to search and analyze them (all hospitals), (2) published evaluations do not apply to their setting (all hospitals), (3) decision-makers have no expertise in appraising evaluations (5 PC and 8 PH), (4) budgets of different hospital units are closed, and costs avoided by the inclusion of a drug cannot be shifted to the pharmacy budget (3 PC and 10 PH), (5) practitioners are reluctant not to give a therapy for cost reasons (2 PC and 7 PH). The last two barriers seem to have more impact in PH than in PC. CONCLUSION: There are many barriers that prevent the use of economic evaluations in hospital formulary decision-making. The barriers related to the decision-making context seem to be very important, especially in PH, financed on a global budget basis. More research is needed to determine the decision-makers' needs for cost-effectiveness information and the incentives to take it into account.