Objective Evaluate the influence of changes in employment conditions on mental health of migrant workers in Spain, in the context of economic crisis.

Methods Follow-up survey at two time points: 2008 and 2011, whose reference population consists of 318 workers from Colombia, Ecuador, Morocco and Romania living in Spain. Those who reported good mental health (n = 214) at 2008 were selected to evaluate, after three years, the incidence of poor mental health according to several sociodemographic and occupational factors (sex, age, nationality, education level, occupation and employment status), and the association between this health indicator and different employment trajectories during this period, by means of adjusted odds ratio (aOR).

Results There is an increased risk of poor mental health in those workers who lost their employment (aOR = 3.62; IC 95%: 1.64–7.96), who increased the number of work hours (aOR = 2.35; IC 95%: 1.02–5.44), whose monthly income decreased (aOR = 13.61; IC 95%: 1.49–124.35) or persisted in the lowest income range (aOR = 14.56; IC 95%: 1.46–144.89). This was also the case for those workers who continued their temporary documented (aOR = 5.05; IC 95%: 1.39–18.34) or undocumented (aOR = 36.59; IC 95%: 2.47–541.17) status. A decreased risk was observed in workers who became affiliated to the Social Security (aORa = 0.10; IC 95%: 0.02–0.48).

Conclusions There is an increase of poor mental health in immigrant workers in Spain related to the worsening of their employment conditions. At the same time, it was observed a decrease when Social Security protection increased.