The American Cancer Society estimated that 576,000 invasive cancers would be diagnosed among American women in 1994 and that 255,000 women will have died of cancer during that year. Six cancers account for almost 70% of the cases in women and more than 60% of the deaths. Risk factors associated with breast, lung, colorectal, cervix uteri, corpus uteri, and ovarian cancers are presented. The patterns of occurrence in the population, time trends, survival rates, and etiologic factors vary considerably, suggesting a constellation of diseases in women. One of the most important factors influencing outcome is early diagnosis.