The results of a phycological study on the chrysophyte flora in the eastern Pyrenees (Catalonia, Spain) are presented. The studied area is located between 1600 and 2600 m above sea level, on primarily acid substrate. A total of 34 taxa have been identified, 25 of which are new or very rarely known in Spain. Information about the cell morphology and ecological data of the studied aquatic systems are presented.