The study of the human ABO blood system is of high significance for the anthropological characterization of a population. For the aims of the present study there have been examined in view to ABO blood group system 237 individuals, as well as and 245 individuals according to Rh system - of both genders. The studied contingent represents a heterogeneous student group from eastern Thessaly Region, Central Greece. Among the sample blood group 0ap showed the highest frequency - 39,66% whereas most rare was AB (9.28 %). Gender differences regarding the frequency of blood groups 0 and A were also established. 86.93% of individuals have positive Rh factor. Rh - positive is more frequent among women - 90.08% , and Rh-negative in men (9.92%). The comparison of the obtained genetic frequencies with older data showed heterogeneity among local Greek populations in comparison with some more distant ones. Accumulation of further data is needed, in order to solve the questions arisen.
