Background: Infant mortality of ethnic minorities in The Netherlands (10% of the population) is twice as high as in the indigenous Dutch population. Causes of death are different for the diverse migrant groups. Methods: Hospital records of nearly 600 infants who died in the four major cities between 1995 and 1998 were analysed according to the cause of death, ethnicity, and possible hereditarity. Results: There was a four to five times higher proportion of hereditary causes of death in the Moroccan and Turkish population, compared with the Surinamese/Antillians and indigenous Dutch. Conclusions: This might be explained by a high inbreeding coefficient as three-quarters of the marriage partners are recruited from the home villages and between a quarter and a third of these marriages are between first cousins. Health promotion activities in The Netherlands have not been successful so far. Preconception genetic counselling might help in reducing these differences.