We tested the hypothesis that the increased incidence of schizophrenia among Surinamese immigrants to The Netherlands could be explained by a similarly high incidence in Surinam. We conducted a 1-year first-contact incidence study in Surinam and compared the findings with data from a similar study conducted in The Netherlands using the same inclusion criteria and instruments. The risk of developing a schizophrenic disorder was 2.4 times higher (95% CI 1.3-4.2) in Surinamese immigrants than in residents of Surinam. The increased risk is probably due to environmental factors in The Netherlands.