Senior centers provide social, health, nutritional, and recreational services to older adults. Ten percent of older adults in these settings experience clinically significant depression. Although many aging services now screen for depressive symptoms, an IOM report indicates that the number of geriatric mental health providers nationally is insufficient. Further complicating treatment delivery is the reluctance of depressed elders to accept a mental health referral or pursue treatment. It has been proposed that lay workers may be able to offer psychosocial interventions for geriatric mental health disorders. Lay volunteer-delivered interventions may improve depression outcomes, may do so by engaging the same target variables as professionally-delivered interventions, and may be both more cost effective and acceptable to seniors. Limitations include uncertainties about training and supervision needs, reliable methods to assure intervention fidelity and patient safety, and comparability of outcomes to those attained by professionally- delivered interventions. Building on senior centers' volunteer programs, this proposal utilizes senior volunteers to meet the mental health needs of depressed urban clients. To this end, the investigators simplified Behavioral Activation (BA) to match the skill set of lay senior volunteers (Volunteer BA). The investigators chose BA because it is an effective treatment for late-life depression, can be administered by paraprofessionals, and its primary mechanism (target) of action has been validated by efficacy studies. Based on preliminary data, the investigators aim to test the feasibility and acceptability of Volunteer BA for an underserved and difficult to engage population. The investigators propose further developmental work on the delivery of Volunteer BA in senior centers, so as to arrive at a sustainable intervention with standardized procedures. The investigators propose a small RCT testing the impact of Volunteer BA versus MSW-delivered standard BA on increased client activity (the target) and reduced depressive symptoms (clinical outcome). The Volunteer BA delivery model: 1. Makes use of existing volunteer resources; 2. has potential for being an acceptable and sustainable intervention; and 3. is expected to engage BA targets. However, its capacity to yield comparable outcomes to MSW-delivered BA is yet to be determined.