Abstract Chromosome numbers for 13 species of Hieracium L. s.str. from Bulgaria, Macedonia, Poland and Romania are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. djimilense s.lat. 2n=3x=27, H. fiekii R. Uechtr. 2n=3x=27, H. glabrescens (F. W. Schultz) Murr 2n=3x=27, H. juranomorphum Zahn 2n=3x=27, H. sparsiflorum subsp. sparsiceps Zahn 2n=3x=27 and H. sparsum subsp. naegelianiforme Behr & Zahn 2n=3x=27.