In this article the authors seek an answer to the question: does the percentage of women working in an industry have an effect on earnings distinct from the effect of sex at the individual level? On the basis of the 'comparable worth' approach, the authors hypothesized that, controlling for education, experience and sex, the percentage of women working in an industry would have a negative effect on earnings. This hypothesis was tested by performing multi-level analyses using data from 12 countries. The hypothesis was confirmed: the multi-level analyses showed a significant negative effect of the percentage of women in an industry on individual earnings, when individual characteristics were controlled for. This effect applied equally for men and women working in an industry. Part, though not all, of the effect could be accounted for by the fact that female-dominated industries are less unionized and more characterized by small firms than male-dominated industries.