This report presents results of an interview study made by the National Institute of Senior Centers (NISC), a program of The National Council on the Aging, Inc. (NCOA). Thirty Centers were selected for on-site study. The criterion was a program directed to older adults, meeting at least once weekly on a regularly scheduled basis and providing some form of educational, recreational or social activity. Sites included at least one Center within each of the 10 HEW regions. Selection of 20 other Centers was determined by systematic examination of two mail questionnaires submitted by Senior Centers themselves. From intake data supplied, NISC staff members assigned to the project selected, at random, persons to be interviewed at the Center. Appointments were arranged in advance. Interview time averaged 50 minutes per individual over a period of five man-days. Case studies of the 30 sites visited reveal implications of the findings, policy recommendations made -- and problems, possible solutions and topics in need of further discussion. It is anticipated that the findings reported here may be useful to those responsible for planning and implementing Senior Center and other group programs. (Author)