This paper demonstrates the extent to which married women's labor supply elasticities have changed over the past quarter century. Estimates from March Current Population Survey data suggest that these elasticities have decreased substantially, by 60 percent for the hours wage elasticity (from 0.36 to 0.14), 70 percent for the hours income elasticity (from -0.053 to -0.015), 95 percent for the participation wage elasticity (from 0.66 to 0.03), and 60 percent for the participation income elasticity (from -0.13 to -0.05). Changing demographic characteristics explain little of the drop in these elasticities, suggesting that preferences toward work have changed across birth cohorts. (Contains 28 footnotes, 13 figures, and 3 tables.) [This article was produced by University of Wisconsin Press, Madison, WI.]