The Telephonic Assessment, Support, and Counseling Program (TASC) was developed to improve access to behavioral health assessment, counseling, and evidence-based psychotherapy in a public health system with an underserved, diverse population. The program is described in detail with examples of materials that can be replicated in other sites. TASC was designed to augment the management of depression provided through primary care clinics, which is where most people in the United States receive treatment for depression. The program used behavioral activation treatment for depression (BA), a well-researched evidence-based form of cognitive behavioral therapy that can be delivered by telephone in a relatively brief time period. TASC also incorporated motivational interviewing (MI) strategies into medication adherence and depression counseling. The intervention was conducted with primary care patients diagnosed with depression by their PCPs through five telephone calls targeting education about depression, medication adherence, and strategies to teach patients to monitor their mood and daily activities and to increase the number of specific activities in which they engage. Prior to beginning BA treatment, the Patient Health Questionnaire-9 and the Mini-International Neuropsychiatric Inventory were conducted to effectively identify alternative diagnoses or serious comorbidities. Primary care clinics providing medical care to low-income, diverse populations have many patients who could benefit from contact with a mental health provider, and telephonic delivery of these services in a program such as the TASC model may be a viable and cost-effective option that can increase access.