The Soviet Union suffered devastating population losses during World War II, currently estimated at 27 million or nearly 14 percent of the prewar population. The disproportionate deaths of young men resulted in a drastic change in sex ratios among the population surviving the war. For example, the ratio of men to women in the 20-29 age group declined from .91 to .65 between 1941 and 1946. I use this large, exogenous change to identify the effects of unbalanced sex ratios on marital, fertility and health outcomes among women in the Russian and Baltic republics in the postwar period. The results indicate that women in cohorts or regions with lower sex ratios experienced lower rates of marriage and fertility, and higher rates of out-of-wedlock births, abortions, and deaths from abortions than women in cohorts or regions less affected by war deaths. Men in cohorts with high sex ratios invested in more human capital than men in low sex ratio cohorts. The evidence is also suggestive of second-generation effects, with the male children of women in high-sex ratio cohorts attaining better health and nutritional status (as measured by adult height) than the children of women in low-sex ratio cohorts.