The chromatographic profiles of carotenoids from some marine shellfish are reported. The analyses were performed both by gradient elution reversed-phase and isocratic direct phase high-performance liquid chromatography (HPLC), and the results obtained are compared and discussed. The six main carotenoids extracted from three shellfish species (Chlamys opercularis, L., Cardium tuberculatum, L., Pecten jacobaeus, L.) were isolated in highly pure form by means of semi-preparative HPLC. They were characterized by means of spectroscopic methods (visible absorption and infrared spectroscopy), and chemical tests: the identification of fucoxanthin and alloxanthin was possible while a tentative identification of two other carotenoids (fucoxanthinol and diatoxanthin) was suggested. Carotenoids in clams and scallops were present both in esterified and free form, while in cardia only carotenoid esters were detected.