Planktonic foraminifera have been examined from eight DSDP sites in the southwest Pacific from the late Early Miocene to the Recent. The traverse of sites examined ranges from tropical to cool subtropical (temperate) regions. The stratigraphic ranges of the planktonic foraminifera of Middle to Late Cenozoic age in six of these sites are presented here. Large paleoenvironmental differences between the sites have made it necessary to use separate zonal schemes in cool subtropical (temperate), warm subtropical, and tropical areas. The planktonic foraminiferal zonations for the cool subtropical and warm subtropical regions are new. For the tropical sites the zonation scheme is that of Banner and Blow (1965) and Blow (1969). Species of Globorotalia represent the most useful forms for zonal subdivision and correlation with the region. In cool subtropical areas a valuable evolutionary bioseries is represented by gradation from Globorotalia miozea conoidea to G. conomiozea to G. puncticulata to G. inflata. In warm subtropical areas the evolution can also be observed from G. puncticulata to G. inflata. The ranges of numerous planktonic foraminifera differ markedly between the different regions because of the distinct environmental controls. Sphaeroidinella dehiscens is of no value in the determination of the Miocene-Pliocene boundary throughout the area because it does not appear until the Middle Pliocene. In cool subtropical areas the first evolutionary appearance of Globorotalia puncticulata marks the boundary, while in warm subtropical areas this species appears later. In the warmer sites the first appearance of Globorotalia margaritae seems to be a reliable indication of the Miocene-Pliocene boundary. The Pliocene-Pleistocene boundary is placed at the first appearance of Globorotalia truncatulinoides. In several sites the evolution of G. truncatulinoides from G. tosaensis near the boundary is not a simple continuum, but is marked by reversals in evolutionary trend that may be partly enviromentally controlled. Most of the important forms are illustrated by scanning electron micrographs.