The present study aims at establishing methods of health administration of people with mental retardation in the institution . The causes and death of people with mental retardation (number examined: 968 persons) over a long period of time were epidemio logically surveyed, focussing on its time trend . And the following results became clear. In profound and severe mental retardation, the prenatal causes were more frequently identified the perinatal and postnatal causes (p<0.001), and the proportion of the prenatal causes was constant, contrasting to the reduction of that of the postnatal ones. Consequently, the difference has become larger recently . On the other hand, people with mental retardation has become aged as a whole. Epilepcy was the most common complication attached to mental retardation . The subjects whose causes were originated in the prenatal period have high prevalence of heart defects, hepatitis and obesity. The death rates of people with mental retardation were higher than those of nonmental retardation in all age class . The causes of death have changed from infectious diseases to chronic diseases . The acquired heart defects were recently the most responsible to death among the complications such as epilepcy, hypertention and hepatitis.
