Physical aggression among institutionalized mentally retarded persons arouses great social concern. To examine the effectiveness of four-point mechanical restraints and a positive adaptive symbol program in the reduction of high frequency, high intensity aggression, three institutionalized severely mentally retarded adolescents (2 females, 1 male) participated in individually designed treatment programs. For each individual, targeted behaviors were identified and recorded. Immediately following an incident of targeted aggression, the subjects were physically restrained in bed in a supine position for a specified period of time. Following restraint, the subjects participated in the symbol program, consisting of wearing a symbol reinforcer (e.g., hat, wristband), and verbal, social, edible, and tangible reinforcers. An analysis of the results showed that four-point mechanical restraint procedure when used in combination with the adaptive symbol program significantly reduced the frequency and intensity of physical aggression, with an average reduction in aggressive behavior of 83 percent reported amongst the three subjects. These findings suggest that contingent restraint can be a useful technique when used in combination with other procedures. (BL)