This report focuses on the transition situation of mentally retarded (MR) youth in Allegheny County, Pennsylvania. The county is served by two Intermediate Units: IU2 (1170 MR students) serves the Pittsburgh School System and emphasizes mainstreaming, with the mildly handicapped attending neighborhood schools and severely handicapped attending a special school; IU3 (2301 MR students) serves the 42 suburban school districts and emphasizes special education centers. Statistical and descriptive data and descriptions of services are provided concerning educable (EMR), trainable (TMR), and severely/profoundly (SPMR) retarded students and former students. Data are also provided from two recent follow-up studies, one of mainstreamed EMR school leavers and the other of EMR, TMR and SPMR graduates of special education centers. The systems serving MR youth and the way contact is made with these systems are described. Local developments intended to improve extant conditions are also described. Recommendations regarding work alternatives for MR youth, interagency cooperation and data gathering, tracking and reporting are included. (KM)