O presente artigo tem como objetivo discutir conceitualmente a nocao de precariedade do trabalho, tendo em vista que ela e amplamente utilizada na sociologia, sem que um significado preciso seja formulado. Propoe-se uma abordagem relacional e construtivista, que procura articular as condicoes objetivas e subjetivas de producao do fenomeno em questao. Para tanto, parte-se do debate sobre o conceito de trabalho, a fim de melhor definir em que consiste sua precariedade. Argumenta-se, igualmente, a necessidade de situar esse debate no âmbito de quadros teoricos mais amplos de interpretacao sociologica. Identificam-se duas dimensoes cruciais na analise da precariedade do trabalho, a relacao de emprego ou trabalho e a atividade laboral propriamente dita, discutindo-se exemplarmente as perspectivas teoricas de dois autores franceses especialmente interessados nesse tema: Robert Castel e Serge Paugam. Finalmente, discutem-se algumas implicacoes desse debate para a realidade brasileira, sustentando-se a importância de dar um tratamento multidimensional ao fenomeno. Palavras-chave: Trabalho. Emprego. Precariedade. Precarizacao. Desigualdade. WORK, EMPLOYMENT, INSTABILITY: conceptual dimensions in debate Francisco Beckenkamp Vargas The present article aims to discuss conceptually the notion of work instability, having in mind that it is widely used in sociology without a precise definition. It is proposed a relational and constructivist approach that seeks to articulate objective and subjective conditions of the production of the phenomenon studied. In order to do this, this study starts with a discussion about the concept of work intending to define, more appropriately, what constitutes its instability. It is equally debated the necessity of situating this debate in the ambit of broader theoretical frameworks of the sociological interpretation. Two crucial dimensions are identified in the analysis of work instability, the relation of job or work with labor activity itself, discussing the exemplary theoretical perspectives of two French authors who are especially interested in the subject: Robert Castel and Serge Paugam. Finally, some implications of this debate are discussed for the Brazilian reality, sustaining the importance of giving a multidimensional treatment to the phenomenon. Keywords: Work. Job. Instability. Precarity. Inequality. TRAVAIL, EMPLOI, PRECARITE: des dimensions conceptuelles en debat Francisco Beckenkamp Vargas L’objectif de cet article est de discuter, en termes de concepts, la notion de precarite du travail, etant donne qu’elle est largement utilisee en sociologie sans que soit formule a son egard un signifie precis. Une approche relationnelle et constructiviste est proposee qui essaie d’articuler les conditions objectives et subjectives de production du penomene en question. Nous commencons donc par le debat concernant le concept de travail afin de mieux definir en quoi consiste sa precarite. Nous insistons aussi sur le besoin de situer ce debat dans le contexte des cadres theoriques plus larges d’interpretation sociologique. Nous identifions deux dimensions cruciales dans cette analyse de la precarite du travail, la relation d’emploi ou de travail et l’activite de labeur proprement dite. Nous discutons a titre d’exemple les perspectives theoriques de deux auteurs francais particulierement interesses par cette question : Robert Castel et Serge Paugam. Finalement, nous abordons quelques implications de ce debat dans la realite bresilienne et nous affirmons qu’il est important d’adopter une approche multidimensionnelle du phenomene. Mots-cles: Travail. Emploi. Precarite. Precarisation. Inegalite. Publicacao Online do Caderno CRH no Scielo: http://www.scielo.br/ccrh Publicacao Online do Caderno CRH: http://www.cadernocrh.ufba.br http://dx.doi.org/10.1590/S0103-49792016000200008