We investigated the chromosome number and morphology of five Centaurea species belonging to five different Centaurea sections. All material analyzed was diploid with chromosome number 2n=18 or 2n=20. Chromosome number 2n=18 was found for two populations (specimen a and specimen b) of Centaurea cassia Boiss., a rare species from Sect. Jacea (Mill.) DC., and two populations (specimen a and specimen b) of C. ptosimopappa Hayeka, a local endemic belonging to Sect. Ptosimopappus O. Hoffm. A chromosome number of 2n=20, however, was observed for the other three Centaurea species: C. arifolia Boiss., a local endemic from Sect. Cynaroides Boiss. ex Walp., C. antochia Boiss. var. antochia, an endemic variety belonging to Sect. Acrocentron (Cass.) DC., and C. hyalolepis Boiss. from Sect. Calcitrapa DC. The chromosome number for the latter species represents the first record for Hatay province. Differences in chromosome size and karyotype are described.