Data obtained from Statistics Canda were presented on the mortality level and expectancy of life for profoundly retarded and severly and moderately retarded persons in Canadian institutions for 1966 through 1968. Previous studies of mortality statistics were reported in mortality rates, average age at death and crude death rates, which are affected by the age distribution of the population involved. The very young and the very old are underrepresented in institutions, and thus these measures are not as accurate as life expectancy tables, which present the number of years expected to live, are independent of age distribution, and provide a reliable statistical measure for future replication and international comparisons. Retarded persons in institutions are living longer than previously, but their life expectancy does not meet that of the general population. Estimates of life expectancy for this population are vital for planning purposes.