Detailed information is provided about the characteristics, needs, and service arrangements of 370 elderly persons with mental retardation living in 235 residential facilities operated or licensed by state developmental disabilities agencies. Representative national samples of foster care homes, small group homes, large private facilities, and large state-operated residential facilities that serve mentally retarded residents aged 63 and older were selected. Directors of day programs attended by sample members were also interviewed. State policies and practices were gathered through surveys of developmental disabilities and aging agencies and other data analysis. Survey results focus on the following topics: (1) careproviders (characteristics, experience, training, and involvement with other careproviders); (2) residential facilities (type of operation, location, size, history, staffing, licensure, reimbursement); (3) resident characteristics, including demographics, sex differences, legal status, level of mental retardation, additional diagnoses, independent living skills, adaptive equipment, communication skills, community living skills, and problem behavior; (4) health needs and related services, covering health-related limitations, medical care required, medications, hospitalizations, etc.; (5) social, leisure, and community activities; (6) day programs (extent of participation, hours of participation, external versus internal day programs); (7) surveys of state agencies; and (8) analysis of data from the National Nursing Home Survey of 1977. (JDD)