PIP: An average of 30 years has been added to Mexican life expectancy in the past five decades. Women and men born in 1940 had life expectancies of 41.5 and 39.5 years, respectively, compared to 72.8 and 66.7 in 1990. Mortality declined most sharply between 1940 and 1960, and declined at varying rates in the subsequent decades. In the decade from 1980 to 1990, the mortality decline slowed. The differential in life expectancy between men and women amounted to 6.2 years in 1980 and 6.1 in 1990. The high life expectancy of women means that future advances will be more difficult to achieve. The greater survival of Mexicans over the five decades is due to improvements in living conditions, advances in preventive and curative medicine, and social policy. The slower pace of mortality decline in the past decade may perhaps have been due to deteriorating living conditions, reduced priority accorded to social policies in the areas of health and education, and declining real incomes. Mexican health, education, and other social policies have favored the urban and industrial centers, increasing regional disparities. A comparison of life expectancies in Oaxaca, one of the most impoverished states of Mexico, and Puebla, which has somewhat better conditions, with life expectancies in the wealthy state of Nuevo Leon and the Federal District demonstrates the influence of the level of development on life expectancy. Life expectancy in 1990 in Oaxaca and Puebla was the equivalent of that for all of Mexico ten years earlier. Men in Oaxaca live five years less on average than men in Nuevo Leon. But the gain in life expectancy for males was higher in Oaxaca between 1980 and 1990 than in the other states.^ieng