At least seven groups of ungulates occurred in South America during the Tertiary: Litopterna, Notoungulata, Astrapotheria, Xenungulata, Pyrotheria, Didolodontidae, and kollpaniine mioclaenid condylarths. Astrapotheria and Litopterna also occurred in Antarctica. Condylarths from North America and Europe are diverse and numerous and evolutionary relationships of South American ungulates with several of them have been suggested. A phylogenetic analysis of representatives of most living placental mammal orders, several groups of North American and European condylarths, and three groups of South American ungulates (Litopterna, Notoungulata, and Astrapotheria) is presented here. The analysis is based solely on postcranial characters. There is very limited information available about the postcranium of South American condylarths, xenungulates, and pyrotheres; therefore they are not included here. The cladogram indicates that litopterns and notoungulates are sister taxa, with the phenacodontid Meniscotherium as their closest North American relative; Astrapotheria would have shared a common ancestor with Periptychida.