An exploratory study was carried out in three European countries – Denmark, United Kingdom and the Netherlands – concerning the safety of migrant workers, especially those coming from Eastern European countries. Special attention was given to the relationship between safety and the national background of migrant workers. Forty-four interviews with HSE experts – e.g. regulators, union representatives – in the three countries, a survey using the NOSACQ-50 safety climate questionnaire and an accident data analysis using Danish data have been combined to draw a picture of the situation of migrant workers in the three countries. Although much data is still anecdotal it is concluded that these workers form a vulnerable group. As long as many migrant workers remain unregistered in the country where they work and national accident databases are not sufficiently or systematically coded, the magnitude of the migrant worker problem remains largely elusive.