PGP electrophoretic polymorphism was studied in a sample of 548 blood donors from the province of Bologna, Italy. Haemolysates were typed by thin starch-gel electrophoresis, a modification of Barker and Hopkinson's method [1978]. The distribution of PGP phenotypes and gene frequencies in Italy varies considerably. The pattern observed in the Bologna sample agrees with the data from northern Italian regions and comparisons show that PGP*2 and PGP*3 gene frequencies tend to decrease along a north-south cline. Sardinia shows a peculiar distribution of gene frequencies where the PGP*2 allele is very low and the PGP*3 allele is absent. The world PGP gene frequencies appear to be distributed along a north-south cline.