Preliminary data on the genome size of representatives of the genus Chondrilla (Asteraceae) of European Russia and Western Kazakhstan were obtained using fl ow cytometry. Among all studied specimens of the genus, for specimens of C. ambigua and C. pauciflora, a direct dependence of the genome size on the number of chromosomes was established. In our study, the DNA content of the diploid C. ambigua was 2С = 1.69 pg, and that of the triploid C. pauciflora was 2С = 2.65 pg.