Data on women in labor unions in 1988 reveal the following facts: (1) women are becoming an increasingly important part of membership in organized labor, as the total number of workers in unions declines; (2) in 1988, nearly 6 million of the 47.5 million employed women in the United States, or about 13 percent, were members of unions; (3) since 1983, the proportion of employed women who belong to unions has declined; (4) membership growth was the greatest among black women; (5) labor organizations seem to be appealing mainly to government workers who are in the skilled professions and technical, clerical, and protective service jobs at all levels where women are heavily employed; (6) in 1988, median weekly earnings for women union members were more than $100 higher than for nonunion women workers, but union women continued to earn over $100 less weekly than union men; and (7) women's participation in labor unions has been most visible in the role of organizers. (KC)