Eight individuals with mental retardation and imposed mechanical restraints due to severe, life-threatening self-injurious behavior received electrical aversive treatment. Eight other individuals, who had been matched with the treatment group in terms of the degree of imposed mechanical restraint due to the above problem behavior, had not received electrical aversion treatment. A comparison of imposed mechanical restraint scores, as a measure of severity of self-injurious behavior, between both groups over a period of three years, revealed that electrical aversion treatment significantly reduces the degree of imposed mechanical restraint.