The Equal Opportunities Spanish Law (from 2007), establishes that those companies with more than 250 workers have to design and implement an equal opportunities plan between women and men. Since the “cost-benefit” relation of equal opportunities has not been yet studied, companies have to convince themselves about the convenience of designing and adopting an equal opportunities plan by means of non quantitative reasons. In this paper the main advantages of equal opportunities for companies are discussed, and some criteria are offered for its application.