Purpose: Expectations regarding aging (ERA) in community-dwelling older adults are associated with personal health behaviors and health resource usage. Clinicians' age expectations likely influence patients' expectations and care delivery patterns; yet, limited research has explored clinicians' age expectations. The Expectations Regarding Aging Survey (ERA-12) was used to assess (a) age expectations in a sample of primary care clinicians practicing in the United States and (b) clinician characteristics associated with ERA-12 scores. Design and Methods: This study was a cross-sectional survey of primary care clinicians affiliated with 5 practice-based research networks, October 2008 to June 2009. A total of 374 of the 1,510 distributed surveys were returned (24.8% response rate); 357 analyzed. Mean respondent age was 48.6 years (SD = 11.6; range 23-87 years); 88.0% physicians, 96.0% family medicine, 94.9% White, and 61.9% male. Results: Female clinicians reported higher ERA-12 scores; clinicians' age expectations decreased with greater years in practice. Among the clinicians, higher ERA-12 scores were associated with higher clinician ratings of the importance of and personal skill in administering preventive counseling and the importance of delivering preventive services. Agreement with individual ERA-12 items varied widely. Implications: Unrealistically high or low ERA could negatively influence the quality of care provided to patients and patients' own age expectations. Research should examine the etiology of clinicians' age expectations and their association with older adult diagnoses and treatment. Medical education must incorporate strategies to promote clinician attitudes that facilitate successful patient aging.