Profiles of the radioisotopes 2 1 0 Pb and 1 3 7 Cs were determined in 15 sediment cores collected from Sagami Bay, Japan. The activities of 2 1 0 Pb e x (unsupported) in core top sediments increased with water depth from 25 dpm g - 1 on the upper continental slope off the mouth of Tokyo Bay to an average of 283 dpm g - 1 at the deep-sea station SB. The high 2 1 0 Pb trapping efficiency of settling particles expected from the results of the sediment trap experiment near the SB site suggests that effective 2 1 0 Pb enrichment in surface sediments may occur during resuspension and lateral transportation of particles via the benthic nepheloid layer on the continental slope. In several cores, 1 3 7 Cs profiles showed an increase, a distinct peak, and then a decrease to an undetectable level downcore. These profiles can be compared with the temporal change of bomb-produced 1 3 7 Cs fallout.The mean sedimentation rates estimated by the 2 1 0 Pb e x inventory method, rather than using 2 1 0 Pb e x profiles, ranged from 0.06 g cm - 2 y - 1 to 0.14 g cm - 2 y - 1 . The average value of the rates in SB cores was calculated to be 0.11 g cm - 2 y - 1 , which was similar to that calculated under the assumption that the age of the 1 3 7 Cs peak corresponds to its maximum fallout year in 1963.Although 1 3 7 Cs inventories represented one tenth of the anthropogenic fallout of 1 3 7 Cs until 1997, they correlated with the increase in 2 1 0 Pb e x inventory. This suggests that the scavenging of refractory 1 3 7 Cs as well as 2 1 0 Pb by settling particles in the water column can lead to the formation of a time marker layer even in deep-sea sediment core, such as at the SB site.