In this investigation are studied 200 individuals of both sexes (100 men and 100 women) of the contemporary Bulgarian population from the region of Petrich. It were studies the blood-group systems ABO and Rhesus factor by means of standard test serums. The explored contingent shows the characterisic for the Bulgarians arrangement of the blood groups at the system ABO: A - 50%, O - 21.5%, B -19,5% and AB - 9%. At comparison with the data for the Bulgarian population (Todorov 1998-1999 - 1080 individuals) it was established higher values at the group A, B and AB more little value at the groups. It were reported significantly statistical differences with Bulgarian population (k=3, x2 = 44,054, p < 0,001) and Greek population, which are separated only by the state boundary (k=3, x2 = 45,570, p < 0,001). At the Rhesus system the data entirely coinsided. .
