The aim of this paper is to analyze the gender gaps present in collective bargaining in Uruguay, between 1945 and 1963. During this period, the number of occupations and activities that signed collective agreements increased and this research presents the main results in terms of the general evolution of the wage arrangements agreed to. Furthermore, the wage arrangements established in the different branches of activity are analysed, as well as in different occupations, according to the skill level. The results show that, although there was no explicit definition regarding the gender perspective in the negotiations, its absence contributed to a deepening of gender inequalities in the collective bargaining process. This does not imply assigning the responsibility of gender inequality to the instrument of negotiation, but it does mean that it was not used to its fullest potential in order to identify, analyze and correct inequalities generated in the labor market and in the specific productive structure of the country.