The objective of this study was to identify conditions that influence primary care clinicians' referral decisions related to depression care. Forty primary care clinicians (15 general internists, 10 nurse practitioners, and 15 family practice physicians) were included in this study. The clinicians participated in semistructured interviews and completed two quantitative instruments (with 33 items on depression treatment decision making and 32 items on provider attitudes toward psychosocial care). Data analysis revealed that several conditions influence a clinician's decision to refer a depressed patient to a mental health specialist: the patient's resources, the clinician's comfort in prescribing antidepressants and counseling patients with depression, and familiarity with a mental health specialist and practice environment. The decision to refer a patient with depression to a mental health specialist is a complex process involving the clinician, patient, and practice-related issues. Understanding these relationships may provide strategies to improve depression care management and lead to the design of depression care quality-improvement interventions that accommodate primary care practice context. The findings from this study suggest a need to increase mental health training opportunities for primary care clinicians to strengthen their skills and comfort level in managing depressed patients and encourage the development of relationships between primary care clinicians and mental health specialists to facilitate timely and accessible mental health care for patients.