A study of carotenoids in 19 specimens of Cladonia grayi from North America revealed the presence of /J-carotene, a-carotene, /J-cryptoxanthin, zeaxanthin, lutein, antheraxanthin, hydrox- yechinenone, canthaxanthin, astaxanthin, violaxanthin, mutatoxanthin, neoxanthin and capsochrome. The total carotenoid content and percentage content of lutein, zeaxanthin, antheraxanthin and violax anthin in investigated materials were dependent on the degree of insolation. Cladonia grayi, insolation, carotenoids, xanthophyll cycle