Life expectancy for persons with Down syndrome has increased dramatically throughout the world over the last 50 years. In 1978 the Israel Ministry of Health initiated a national program for the prevention of birth defects, and since 1979 data on the incidence and mortality of persons with Down syndrome have been collected and analyzed. Data from this register are presented for the period 1979-97 and compared to a previous study from Jerusalem for the period 1964-70. The actual incidence rate in 1997 was 1.1 per 1,000, but the total or true incidence rate (both live births and terminated pregnancies), was 2.32, which was not much different from the 1964-70 rate of 2.43. With regard to mortality, in 1979 45.9% of the children born with Down syndrome died before the end of the first year; in 1966 only 8.6% died. In 1979 57.8% died before the age of 14, compared to only 10.5% in 1996.
