This study describes varying types of nonhandicapped co-worker interactions with supported employees. The sample included 341 supported employees with mental retardation served by community rehabilitation facilities in Illinois. Results indicated that co-workers interact extensively with persons who are mentally retarded. These interactions include associating, evaluating, advocating, training, collecting data, and befriending. Surprising findings included high levels of advocacy between co-workers and persons with severe/profound mental retardation, and a relatively high percentage of co-workers assuming evaluation and training roles. Results are discussed in relation to the work behavior literature which suggest that co-worker interactions may reflect support that is natural to the workplace. Includes 24 references. (Author/JDD)