Nannofossil assemblages, carbonate content and grain size distributions were analyzed in 46 samples of surface sediments collected in the middle and outer shelf of the East China Sea. Thirty three indigenous taxa were identified. Emiliania huxleyi and Gephrocapsa oceanica were the two dominant calcareous nannoplankton species. The former was derived from both the China Coastal Current and the Kuroshio Current. The latter originated mainly form the Japan longshore current. Sediments containing high carbonate content (>30%) were deposited along the shelf break of the East China Sea. About 89% of the total carbonate material was composed of shell fragments and foraminiferal tests. Nannofossils were found mainly in the south of the loop current off the Changjigang River, the western tip of Japan longshore current and in the western flank of the Okinawa Trough.