OBJECTIVES: The purpose of this research was to explore physicians' attitudes and behaviors related to vaccine financing issues within their practice. Amid the increasing number of vaccine doses recommended for children and adolescents, anecdotal reports suggest that physicians are facing increasing financial pressures from vaccine purchase and administration and may stop providing vaccines altogether to privately insured children. Whether these sentiments are widely held among immunization providers is unknown. METHODS: We conducted a cross-sectional mail survey from July to September 2007 of a random sample of 1280 US pediatricians and family physicians engaged in direct patient care. Main outcome measures included delay in the purchase of specific vaccines for financial reasons; reported decrease in profit margin from immunizations; and practice consideration of whether to stop providing all vaccines to privately insured children. RESULTS: The response rate was 70% for pediatricians and 60% for family physicians. Approximately half of the respondents reported that their practice had delayed the purchase of specific vaccines for financial reasons (49%) and experienced decreased profit margin from immunizations (53%) in the previous 3 years. Twenty-one percent of respondents strongly disagreed that "reimbursement for vaccine purchase is adequate," and 17% strongly disagreed that "reimbursement for vaccine administration is adequate." Eleven percent of respondents said their practice had seriously considered whether to stop providing all vaccines to privately insured children in the previous year. CONCLUSIONS: Physicians who provide vaccines to children and adolescents report dissatisfaction with reimbursement levels and increasing financial strain from immunizations. Although large-scale withdrawal of immunization providers does not seem to be imminent, efforts to address root causes of financial pressures should be undertaken.