Context: Little is known about rural clinicians' perspectives regarding early childhood immunization delivery, their adherence to recommended best immunization practices, or the specific barriers they confront. Purpose: To examine immunization practices, beliefs, and barriers among rural primary care clinicians for children in Oregon and compare those who deliver all recommended immunizations in their practices with those who do not. Methods: A mailed questionnaire was sent to all physicians, nurse practitioners, and physician assistants practicing primary care in rural communities throughout Oregon. Findings: While 39% of rural clinicians reported delivering all childhood immunizations in their clinic, 43% of clinicians reported that they refer patients elsewhere for some vaccinations, and 18% provided no immunizations in the clinic whatsoever. Leading reasons for referral include inadequate reimbursement, parental request, and storage and stocking difficulties. Nearly a third of respondents reported that they had some level of concern about the safety of immunizations, and 14% reported that concerns about safety were a specific reason for referring. Clinicians who delivered only some of the recommended immunizations were less likely than nonreferring clinicians to have adopted evidence-based best immunization practices. Conclusions: This study of rural clinicians in Oregon demonstrates the prevalence of barriers to primary care based immunization delivery in rural regions. While some barriers may be difficult to overcome, others may be amenable to educational outreach and support. Thus, efforts to improve population immunization rates should focus on promoting immunization "best practices" and enhancing the capacity of practices to provide immunizations and ensuring that any alternative means of delivering immunizations are effective.