<p>Since 1995, when the Fourth World Conference on Women was held, working with a gender perspective and transversally has become a duty for the public powers. The mandate, however, has had to avoid a number of obstacles, criticism and detractors who, by mistakenly interpreting its meaning, have intended to hinder the advancement towards an actual – not merely formal – gender equality. Despite that, many public policies have included, in their design and implementation, this new analytical tool to understand why the actions taken by the public powers are not<br>gender neutral. In this sense, if there is a field of governmental development where including the gender perspective has not only been necessary, but also compulsory, it is social policies. As a consequence, those who develop their professional career through social policies have had to include it in their daily work. Among them, those we will focus on in this article –social workers. Based on these considerations, the present text intends to show how the gender perspective has been introduced in the field of public policies for prisons in Spain, since this is one of the centres of development of social workers. We will pay special attention to the specificities of this public policy, to the need of using this analytical tool and to the lights and shadows detected in its implementation.</p>