This research employed a model of interorganizational relations (Van de Ven, 1976) based on social action theory to examine the interagency relationships between Title III/Area Agencies on Aging (AAA) and Social Services Block Grant (SSBG) agencies across the country. The specific purpose of this study was to investigate five AAA/SSBG agency relationships using case study methodology to determine the adequacy of Van de Ven’s model in portraying the relationships. I also examined possible changes in the framework that might enhance its ability to characterize the relationships. In general, qualitative data analysis supported the model’s ability to depict the interagency relationships. The following factors were influential in the formation and continued functioning of at least three of the five interagency relationships: (a) resource needs, dependence, and exchange; (b) a commitment to serving older adults; (c) a commitment to the interagency relationship; (d) interagency communication, awareness, and information exchange; (e) interagency consensus (i.e., agreement between agency representatives on the goals and expectations of each agency in the relationship); (f) domain similarity (e.g., overlap in client populations and geographic service areas); (g) informal means of interaction and communication; and (h) perceived effectiveness of the interagency effort by agency representatives. Based upon the results of this investigation, I have proposed a revised framework that incorporates the major components of the original model but also simplifies and conceptually clarifies important relationship factors. It places more emphasis on the individuals involved in interagency relationships and is tailored to fit the special circumstances of social service agencies. An important implication of these findings for further research is the need for examining other social service agencies with the original and revised framework to further enhance their usefulness in characterizing interagency interaction. Implications for practice include the use of this information about AAA/SSBG agency relationships to improve interagency collaboration, service delivery and planning, and public policy decisions. / Ph. D.