The known type specimens of Crocodilia and Testudines in the collection of the Division of Amphibians and Reptiles, National Museum of Natural History, Smithsonian Institution, published through 2006 represent 93 names of taxa. The catalog presents a list of 249 type-specimen records consisting of 39 holotypes, 52 syntypes, 3 lectotypes, 2 neotypes, 132 paratypes, and 21 paralectotypes. The list is arranged alphabetically by family within Crocodilia and Testudines, and alphabetically by genus and species, as described originally within family. Each entry provides both original and current genus and species names, author(s), date of publication, abbreviated type citation, page of original description, and accompanying fi gures and plates (if any), current type status, USNM catalog number, number of specimens, specimen measurement(s), locality, collector, and date collected. Also included for each taxon is the published type locality, type material at other institutions, an etymology, and remarks on corrections or additional data for original type records, changes in type status, and information pertaining to lost, exchanged, or destroyed specimens. An index of scientific names follows the catalog.