This paper reports the first detailed study of lichens on Sable Island since the pioneering study of John Macoun in 1899 who recorded 27 taxa in his publications. The present survey carried out in 2007, revealed that 39 macrolichens and 42 crusts now colonize sand, bone, lignum and cement substrata. The annotated checklist which includes current and former records contains 62 macrolichens and 46 crustose species plus seven lichen parasymbionts. Specimens have been deposited in the Nova Scotia Museum of Natural History, Halifax (nspm) and in the Canadian Museum of Nature, Ottawa (canl). The changes in the lichen flora, and the possible reasons for them, that have occurred over the past 20 years and since the first survey in 1899, are discussed. Speculations on the future of the present lichen flora on Sable Island are also made.