This study used a partial sequence of the mitochondrial cox1 gene for the reconstruction of the interrelationship of the adult and larval stages of Spirometra obtained from Cerdocyon thous, Leopardus munoai, Canis familiaris, Didelphis albiventris and Philodryas patagoniensis in Uruguay. The phylogenetic analysis showed that they were grouped with Spirometra decipiens from the Americas with a high bootstrap support. According to recent studies, American Spirometra species split into two S. decipiens complexes. Our findings strongly suggest that S. decipiens complex 1 is widely distributed in South America, and that wild and domestic canids are definitive hosts. Most of the samples (n = 10) grouped adults and plerocercoids that were retrieved from mammals and reptiles and seem to be the same taxon found in a Lycalopex gymnocercus from Argentina. A second clade was formed with Spirometra sp. found in a L. munoai as well as other wild felids such as a Puma concolor and a Leopardus pardalis (both from Argentina). On the other hand, S. decipiens complex 2 is present in South America and North America. South American clade parasitizes wild (and possibly domestic) felids and reptiles as definitive and intermediate hosts, respectively, whereas the North American clade found in snakes and captive meerkats (acting either as second intermediate or paratenic hosts) has unconfirmed definitive hosts.