The complex process of interaction between different ethnic groups in Transcaucasia in ancient times has been little studied. Undertaken here is a multidimensional craniometric analysis of more than 112 Eurasian ethnic groups between 1st century BC and 3rd century AD. The collected information was submitted to cluster analysis which revealed patterns of genetic difference between the different ethnoses. The results show that the entry of Scythians, Sarmatians and Saka into Transcaucasia and the Armenian highlands involved not only cultural interaction, but also identifiable patterns of genetic admixture.