A large-scale radon survey has been carried out from 1995 to 1998 in southern Greece, in order toestimate the radon concentration in Greek dwellings and the exposure of the Greek population toradon. The design was administratively orientated. The statistical criterion for the selection ofsampling locations and the distribution of radon dosimeters was the percentage of dwellings of eachlevel of the administratively classifications in respect to the above level. This way of distributionassured that all the inhabited geographical regions were covered.