Distributions of 37 species of Radiolaria are determined from 83 samples of Holocene North Pacific sediments. Recurrent group analysis of these distributions allows recognition of six assemblages which reflect present-day surface water circulation and distribution of upper water masses. Relative abundances of “cold,” transitional, and “warm” water recurrent groups in Pleistocene core V20-130 (35° 59’ N., 152° 36’ E.) determine a radiolarian temperature curve which is similar to a previously determined diatom temperature curve. Two temperature maxima and three temperature minima are recognized in the core. One new species is described.