OBJECTIVES: The Academy of Managed Care Pharmacy (AMCP) Format for Formulary Submission (v2.1) is a set of guidelines intended to standardize the clinical and economic information submitted by drug companies to health plans for formulary determination. We examined familiarity with, and use of, the Format among pharmacy directors at U.S. health plans nationwide. METHODS: We obtained a list of U.S. health plans providing prescription drug coverage from the HealthLeaders-InterStudy database as of July 2006. After excluding local affiliates of national or regional plans, there were 257 plans in the sample. Data were collected from May to November 2007 through self-administered questionnaires sent to pharmacy directors or formulary managers. RESULTS: A total of 135 of 257 questionnaires were completed (response rate= 52.5%). Respondents represented plans with over 125 million covered lives (74% of covered lives accounted for by contacted plans). Most health plans maintain formulary decision-making responsibility, though some (especially at smaller plans) use input from pharmaceutical benefit managers (PBMs) to guide formulary decisions. 3/5 of all respondents and almost 90% of those at large plans (>500,000 covered lives) were extremely familiar or familiar with the Format. Approximately 36% of all pharmacy directors (56% of those at large plans) request information from drug firms in an AMCP Format structure. With regard to safety and efficacy for labeled use, health plans were more likely to perceive information provided in Format-compatible dossiers to be complete and clear or easy to understand than information in other presentations. Information related to off-label use and costs and benefits was frequently perceived by plans to be incomplete, lacking in clarity, and biased, regardless of whether it was in a Format-compatible presentation. CONCLUSIONS: Familiarity with the AMCP Format is high among pharmacy directors at U.S. health plans. Adoption of the Format has increased steadily over time, especially among large plans.