The main theories on labor informality are analyzed: the structuralism and the institutionalism. The key contradiction is that the object of the first theory is bad jobs, whilst the object of the second is the fulfillment of institutional arrangements by firms. This paper embodies the institutional vision into the structural in order to develop a more comprehensive theory. Afterwards, data provided by the National Household Survey are shown to be consistent with this new vision. These data are taken from 1988 to 2000 for the even years· informality questionnaire.