This article analyzes the fundamental rights modalization in labor relations, and criticizes the juridical-argumentative tools used to solve confl icts of fundamental rights within the company. For the author, the priciple of proportionality in the broad sense (suitability and necessity) is a tool skewed to the problem of the collision of fundamental rights, because it starts on the basis of the legitimacy of the employer’s actions, giving prominence a priori to freedom of enterprise. Related to this, the author argues that the most appropriate approach that must be applied in fundamental confl icts between the employer and employee, is the proportionality in the strict sense, or weighting.