The present work reports a study of nine genetic polymorphic systems in the area of the Po Delta where malaria was endemic since the XIV century. Our data confirm some characteristics of this population already reported by other authors such as the high prevalence of thalassemia, the low prevalence of the rh (d) gene and the presence of G-6-PD deficiency. Among the other systems studied, i.e., AP, PGM1 ADA and AK, only AP frequencies of Po Delta population are significantly different from those of other continental Italian populations, the PC allele showing the lowest frequency so far observed.