Providing comprehensive services for the elderly in local communities presents planners and potential users with a complex set of problems. The development of new or expanded service to the elderly was examined within an ecologically informed resource dependency model to assess the effect on service expansion of organizational maintenance factors (resource competition, environmental security, organizational dependency), external pressure from planning, funding and community sources, perceptions about service needs and attitudes about problems posed by elderly clients. A survey of 480 human service agencies in 12 metropolitan communities revealed that 88 agencies had expanded to serve the elderly. These agencies were compared with those that had not expanded. The results showed that expanding agencies had significantly higher levels of competition, environmental uncertainty, organizational dependency and need for resources than non-expanding agencies. Their directors perceived expansion through collaboration as profitable for the agency as well as clients. Views about unmet service needs and limited community resources did not differentiate the groups and all agencies reported low external pressure. Expanding agencies' directors considered ageism and problems associated with the elderly less important than did heads of other agencies, and reported lack of funds as the major problem in innovation for the elderly. The findings tend to provide support for the resource dependency model. (Author/NRB)