Analysis of haplotypes of three intragenic, highly polymorphic microsatellite markers (IVS8CA, IVS17BTA, IVS17BCA) of the CFTR gene was performed on a sample of 96 CF chromosomes of Polish origin. Twenty different haplotypes were detected in ΔF508 chromosomes. Of these, four haplotypes (23-31-13; 23-32-13; 17-31-13; 17-32-13) represent 67.1% of the overall pool of ΔF508 chromosomes. Distribution of these haplotypes, together with frequencies of the ΔF508 mutation, are intermediate between Northern- and Southern-European populations and correlate with established gradien