Cross modality is a method for channeling therapeutic services from various health disciplines (modalities) through a single therapist who provides direct treatment and care. A pilot project at the University of Michigan's Institute for the Study of Mental Retardation and Related Disabilities tested this method in three mental retardation institutions. The ward attendant was designated as the primary therapist. The project staff included a physical therapist, speech therapist, occupational therapist, and nutritionist who taught ward attendants selected evaluation and treatment procedures. In theory, cross modality broadens the role of the institutional physical therapist to include teaching, monitoring of physical therapy services, and consulting with an institutional cross modality team which includes therapists (physical, occupational, speech), a dietitian, nurse(s), supervisor(s), and ward attendants. In practice, the therapist's attitude toward cross modality and the receptiveness of the ward attendant determine, the success of cross modality in any setting.