In recent years, there has been a growing consensus that gender diversity could improve the economic and the social performance of companies, although the progress was painfully slow. In Italy, the Law n. 120/2011 required that from 2012 women should be at least 1/5 and from 2015 1/3 of boards. Our first aim is to study the level and the evolution of the presence of female directors on boards of Italian companies over the period 2009-2014. Secondly, we studied the relationship between the number of female directors and firm performance, in order to verify if the presence of women on corporate boards will affect the firm’s performance. We have selected the 30 biggest companies listed on the Milan Stock Exchange, ordered by their total assets. To verify the presence of women on the companies’ boards, for each company we have identified the number of female directors and, with a view to understand the power of them, for each female director, we verified if she is an executive director. With reference to the relationship between the presence of female directors and firm’s performance, we estimated for each year the companies’ ROI. Our first contribution is to do a descriptive analysis of the presence of female directors over the period 2009-2014 among the sample of companies selected. Basically, we want to provide a picture of the Italian situation in terms of gender equality. To our knowledge, this is the first study that focuses on the situation of Italian listed companies over such a long period. The second contribution is to study the women’s power on the board. Essentially, we want to verify if, in addition to the growing number of female directors, there was also an increase of their power. The last contribution is to verify, through a regression analysis, the effects on firm’s performance of the presence of female directors. According to previous literature, we want to test if women on corporate boards can improve firm’s performance. Our research aims to satisfy the following practical questions: – is women’s participation only required by law or there was even before 2012? -do women on boards have really power? -do female directors affect firm’s performance?