Throughout the Greater Antilles, the Virgin Islands, the Cayman Islands, the Bahama Islands, and the Turks and Caicos islands occurs a group of moderate to very large lizards of the iguanid genus Cyclura. These ground iguanas form a conspicuous element of the herpetofaunas of their respective islands. In some areas, the ground iguanas are still very abundant, in others somewhat less so, and in still others they have either become recently extinct or are known only from fossils. Fourteen species are currently recognized, with the largest percentage occurring in the Bahamas Islands. There has been no recent taxonomic treatment of the genus. That of BARBOUR & NOBLE (1916) was the only systematic study, and these authors were very greatly hampered by far from adequate material of many taxa. They examined a total of 22 specimens and named four species, each on the basis of a single individual. We on the other hand have examined 378 preserved specimens. As might be presumed, the characteristics which BARBOUR & NOBLE employed to distinguish species are not always confirmed when longer series of specimens are studied. Accordingly, diagnoses of species of Cyclura may not easily be made solely on the basis of absolute differences in head scutellation or other scale features – the amount of variation in any series is often so great that we have found it impossible to maintain several currently recognized species on absolute scale differences. Rather, scale modalities have been used in part to diagnose taxa. In addition, color and pattern of both adults and juveniles (especially the latter) reveal relationships which would perhaps be more obscure if these data were not available. Nevertheless, there are many problems remaining within the genus, and we feel that our treatment of the various taxa may well be modified as more material is accumulated. We have adhered to a via media in our taxonomic treatment; we have described no new subspecies (although in some cases there are differences which in other iguanid genera suggest subspeciation) but on the other hand we have maintained all names presently in use (although in some cases the subspecies remain rather poorly defined). We have not hesitated to express our opinions in the soundness of our own interpretations in these cases. We have been able to examine such a large quantity of specimens only through the cooperation of the curatorial personnel at several museums, both in the United States and abroad. There exist many other specimens of Cyclura in American collections which we deliberately did not choose to examine; these specimens are often with imprecise locality or other data and are lizards that died in public or private collections and were later preserved. Much of the material we have examined is in the collection of the senior author (Albert Schwartz Field Series – ASFS); specimens formerly in the collection of the junior author have now been catalogued in the ASFS. Between us, we have seen living examples of all but four taxa which we recognize herein.