The distribution of AB0 blood and Lewis blood group phenotypes in 2988 Greek individuals was determined with monoclonal reagents and the results analysed according to their birthplace or that of their parents when they were born in the same region. Overall, the AB0 blood groups distribution was similar to that reported for Greek soldiers in 1919. The only unusual variation was that 29% of the donors born in Thrace were group B. The proportion of Lewis (a-b-) individuals ranged from 1-3%. The frequency of Le (a+b-) donors (non-secretors) ranged from 16% in Thessaly to 27% in East Macedonia, Epirus and those born abroad; the Le (a-b+) frequency was 71-83%.