The final part of a three part study of developmentally disabled persons in Washington State, this document focuses on clients of the Division of Developmental Disabilities (DDD), ages 19 through 26, who appeared to be eligible for DDD services but were not enrolled with the DDD (group C). Telephone interviews were conducted with parents of 55 developmentally disabled adults who were special education graduates and had a handicap consistent with DDD criteria, but were not enrolled in the DDD. Comparisons of group C Ss with DDD clients revealed that group C had higher functional skills and a higher representation in competitive employment. Further, families had a range of services and support available. Data did not support the assumption that there is a sizable population of unserved clients in need of DDD services. Less that 10% of the parents anticipated the need for family support or residential services through DDD, although 45% noted the likelihood of needing vocational training and/or job placement services. A description of methodology and a set of data tables are appended. (CL)