Monthly aragonite fluxes of cosomatous pteropods in the deep Japan Basin in the East Sea (Japan Sea) were estimated using a bottom tethered time-series sediment trap for the 1-year period from July 1994 to August 1995. The trap with 13 time-series sediment collectors was placed at 2.8 km below the surface and 0.3 km above the bottom. It collected setting particles during twelve 30 or 31-day intervals over a total of 365 days. A single species of Limacina helicina dominated the settling pteropods. The annual pterpod flux at the depth of 2.8 km over 12-month period was 2328 individuals m-2yr-1. The fall-winter pteropod downward flux during the period of 19 November to 18 December 1994 may account 67% of the annual pteropod flux.