Siliceous-rich sediments of Late Pliocene to Early Pleistocene age at DSDP Site 278, located on the Antarctic Convergence, contain an excellent radiolarian biostratigraphic and paleoclimatic record. The radiolarian zonation indicates that the Middle Pliocene is missing in a disconformity. Three radiolarian zones are recognized above the disconformity, and from comparison with previous piston core sudies, indicate a continuous biostratigraphic sequence from the early part of the Brunhes Normal paleomagnetic epoch (0.69 m.y. BP) to the earliest part of the Matuyama Reversed Epoch (2.40 m.y. BP). Oscillations in the frequency of the cool-water radiolarian Antarctissa strelkovi indicate 9 or 10 warm-water episodes during that part of the Matuyama Reversed Epoch represented, with one warm-water episode inferred to be missing in the disconformity. The most important radiolarian species are illustrated by SEM and LM photographs.