Karyotypes of 12 Euphorbia species were studied and described for the first time; Euphorbia cheiradenia, E. pannonica, E. pestalozzae, E. petrophila, E. pisidica, E. thessala and E. yildirimli. Karyological analyses indicate relationships among the species with respect to their asymmetry indices. Most of the investigated taxa are diploids with 2n = 2x = 18. E. macroclada and E. smirnovii showed tetraploid cytotypes 2n = 4x = 36. All karyotypes are symmetrical, consisting of metacentric and submetacentric chromosomes. The chromosomes range in size from 0.79 mu m to 2.20 mu m. The total haploid chromosome length (THL) ranges from 8.75 mu m (E. terracina) to 16.78 mu m (E. petrophila). Principal Coordinate Analysis with five uncorrelated parameters was performed to determine the karyological relationships among the taxa.