Abstract The 31 Antarctic cyanobacterial strains, object of this study, were isolated from south polar lake sediments, soil and lichen associations and belong to the genera of Cyanothece, Chondrocystis, Leptolyngbya, Pseudophormidium, Phormidium, Hormoscilla and Nostoc. They are maintained in the Culture Collection of the Istituto per lo Studio degli Ecosistemi (ISE-CNR, Florence). The fatty acid composition varied among the strains, with relatively high quantities of polyunsaturated fatty acids. Arachidonic acid was found in two strains of Phormidium pseudopristleyi at 24% and 32% of the total fatty acid content. The total lipid content and the C/N ratio varied among strains from 13% to 9% and 3.7 to 11.2, respectively. The diversity of saturated and unsaturated fatty acid composition among the Antarctic strains and their possible application as nutrient supplements are discussed.