One of the most important social phenomena in the global context is the flow of immigration from developing countries, motivated by economic and employment related issues. Discrimination can be approached as a health risk factor within the immigrant population's working environment, especially for those immigrants at greater risk from social exclusion and marginalisation. The aim of this study is to research perceptions of discrimination and the specific relationship between discrimination in the workplace and health among Spain's immigrant population. A qualitative study was performed by means of 84 interviews and 12 focus groups held with immigrant workers in five cities in Spain receiving a large influx of immigrants (Madrid, Barcelona, Valencia, Alicante and Huelva), covering representative immigrant communities in Spain (Romanians, Moroccans, Ecuadorians, Colombians and Sub-Saharan Africans). Discourse narrative content analysis was performed using pre-established categories and gradually incorporating other emerging categories from the immigrant interviewees themselves. The participants reported instances of discrimination in their community and working life, characterised by experiences of racism, mistreatment and precarious working conditions in comparison to the Spanish-born population. They also talked about limitations in terms of accessible occupations (mainly construction, the hotel and restaurant trade, domestic service and agriculture), and described major difficulties accessing other types of work (for example public administration). They also identified political and legal structural barriers related with social institutions. Experiences of discrimination can affect their mental health and are decisive factors regarding access to healthcare services. Our results suggest the need to adopt integration policies in both the countries of origin and the host country, to acknowledge labour and social rights, and to conduct further research into individual and social factors that affect the health of the immigrant populations.