In this paper the authors try to analyse the evolution of the formal work market at the Pólo Petroquímico located in the state of Rio Grande do Sul. It concerns speciallythe transformation that has been occurring because of the process of productive reorganization with the use of new organizational, managerial and industrial technologies. The choice of the petrochemical branch and more specifically the pole located in Rio Grande do Sul was due to the little attention given to the transformation in the industries of continuous process and to the importance of this branch of the industry in the state of Rio Grande do Sul. The information concerning this study were gathered from the RAIS - Relação Anual de Informações Sociais (Annual List of Social Information) and from CAGED - Cadastro Geral de Empregados e Desempregados (General Registration of Employees and Unemployees), which are both part of the Ministry of Labor. The data were studied in a period of 10 years, from 1986 to 1996, in a way it could allow the analysis of the evolution of this market and the comparison among different years, ages, level of instruction, average salaries and length of service.