OBJECTIVES:  U.S. healthcare spending on high-cost biologics has escalated over the past decade. The Biologics Price Competition and Innovation Act allows for biosimilar products in the United States, which will be lower-cost alternatives to reference biologics. This study explored payer attitudes to the reimbursement and adoption of biosimilars in the United States. METHODS:  Some 61 U.S. medical or pharmacy directors at managed care organizations (MCOs) were surveyed during 2014 regarding their expectations for biosimilar reimbursement. RESULTS:  Respondents indicate that MCOs expect biosimilars to offer a significant discount to the reference brand to secure reimbursement. A mean discount of 23-24% is considered adequate for reimbursement, while 33-34% is deemed necessary for preferential reimbursement to the reference brand. Rapid formulary inclusion of biosimilars is expected, with 79% of respondents indicating formulary inclusion within 12 months of launch. Widespread reimbursement of biosimilars in extrapolated indications is, however, uncertain, with only 34% of respondents reporting that their MCO would unconditionally reimburse a biosimilar under such circumstances. Payers expect to employ various strategies to promote biosimilar uptake, from favorable tiering to step-therapy requiring biosimilar prescribing prior to the reference brand. The most conducive uptake strategies are expected for products with deep discounts. In addition, payers will run educational campaigns for physicians. However, ≥80% of respondents say their biosimilar approach will likely be influenced by thought-leading physicians and medical associations. Furthermore, widespread “grandfathering” is expected, i.e. continuation of the reference brand in responsive/stable patients. CONCLUSIONS:  U.S. payers will preferentially promote biosimilars over reference brands using various demand- and supply-side measures, so long as biosimilars meet their discount expectations and have clinical stakeholder buy-in. Payers clearly seek to realize the cost savings biosimilars offer; however, tendency to seek clinical stakeholder buy-in, coupled with likelihood of extensive “grandfathering”, indicates some need for more robust evidence of cost-effectiveness.