RESUMO
Workers participation in the management of employment and working conditions is an important determinant of both positive and negative effects of work on human health. Through a qualitative approach, this study analyzes the degree of control and influence that migrant workers in different Spanish cities have over their own working conditions (Immigration, Work, and Health [ITSAL] Project). Results showed that migrant workers had little influence on employment and working conditions. Immigrant workers are mostly interested in issues such as salaries, hiring, and hours of work. Fear of dismissal makes immigrant workers reluctant to demand improved working conditions. We received limited information about immigrant workers' understanding of their rights and their perceptions of the possibilities to influence working conditions through trade union activity. Informal social networks play an essential role in disseminating information on workers' rights, although the effect is not always positive. Unions need to increase attention to and adapt measures for this particularly vulnerable group of workers.