In an ethnically diverse society cultural competence is indispensable for medical doctors. At present 10% of the Dutch population are first- or second-generation non-Western immigrants. With 8% Western and 18% non-Western immigrants, originating from 30 different countries, the 2001 Rotterdam first-year students highly out-rated the national average of immigrant medical students. Diverse student populations may enhance students' cultural competence but can also generate conflicts or even racism. This was the first Dutch study on expectations and experiences of medical students related to their ethnic and religious background. In December 2001 all first-year students were approached with an anonymous questionnaire, including statements on the expected influence of their culture and religion on their medical education (rated on a 1-5 Likert scale). In spring 2003 17 students from the same cohort, 8 immigrants and 9 ethnic Dutch, were interviewed extensively on their study experiences in a diverse student population. In 2001 the response rate was 90% (277/308), female-male ratio 63% (175/102). Non-Western immigrants expected for their medical education more benefits from their culture but also more obstacles than ethnic Dutch (p < or = 0.005). Protestants and Muslims expected more obstacles than the non-religious and Catholics (p < or = 0.05). In the interviews three main issues emerged: peer training in physical examination in mixed-gender groups, lack of attention to student diversity during education, and demand for education in cross-cultural medicine. Three incidents of perceived discrimination were reported. The ethnic Dutch students interviewed did not socialize much with immigrants, nor did students of both groups learn much from one another. Most students favoured mixed study groups. The diversity of the population does not seem to have caused serious problems, nor has it offered educational benefits. The challenge for educators is to provide systematic education in cultural competence and cross-cultural medicine, in which students and educators indeed practise communication across cultural borders.