ABSTRACT: Over 1000 samples from cores and cutting from 37 wells from offshore South America have been investigated and have provided new insight into the evolution of the miogypsinids. For the first time Paleomiogypsina, a genus first described from the Late Oligocene of Japan, is reported from the Early Oligocene of the American province. One new genus, Americogypsina and 18 new species, Neorotalia sp. 1, Paleomiogypsina braziliana, P. americana, Americogypsina braziliana, A. americana, A. koutsoukosi, Miogypsinella elongata, Mlla matsumaria, Mlla sp. 1, Miogypsinoides praegunteri, Mdes sp. 1, Miogypsinodella braziliana, Miogypsina triangulata, M. americoprimitiva, Miolepidocyclina braziliana, Ml. sp. 1, Ml. sp. 2, Ml sp. 3 are described. The American regional evolutionary lineages of the miogypsinids taxa are described, starting in the Early Oligocene and ending in the Early Miocene. Their phylogenetic lineages are similar to those of the Tethyan miogypsinids, however the stratigraphic ranges of the main genera and their species are different, as the American miogypsinids made their first appearance earlier than their morphologically similar Tethyan counterparts.