To describe the factors that affect the use of new combination vaccines, the authors conducted qualitative interviews with pediatricians (n = 7), state immunization program managers (n = 7), and health insurance plan representatives (n = 6 plans). Respondents from each group identified reduction in pain and potentially increased immunization coverage as key benefits of new combination vaccines. For several pediatricians, low reimbursement for cost of vaccine doses and potential loss of fees for vaccine administration were barriers to using combination vaccines. For most state immunization programs, the higher cost of combination vaccines relative to separate vaccines was an important consideration but not a barrier to adoption. Most insurers were not aware of the financial issues for providers, but some had changed or were willing to change reimbursement to support the use of new combination vaccines. Financial issues for pediatric practices that purchase and provide vaccines for children may be an important barrier to offering combination vaccines.