The collection of large volumes of pore water (1-2 liters per 2 cm horizon of sediment) and low level radiochemical measurements of 239,240Pu and 137Cs have been combined to produce the first study of these fallout artificial radionuclides in marine pore waters. Profiles from box cores taken in June and September 1982 from Buzzards Bay, Mass., are reported along with profiles of many diagenetic constituents ( i.e. SO 42-, alkalinity, Fe, Mn, DOC, and nutrients). The 239,240Pu pore water profile is characterized by a subsurface maximum of about 0.28 dpm/100 kg lying between 3-11 cm. Overlying seawater, in contrast, has an activity of 0.01 ± 0.02 dpm/100 kg. Below about 11 cm, the pore water 239,240Pu distribution follows that of the solid phase which decreases rapidly with depth. The pore water profiles of 137Cs are characterized by a broad and deeply penetrating maximum where activities of about 35-40 dpm/100 kg extend from 3 to 20 cm. Overlying seawater, in contrast, has an activity of 17-24 dpm/100 kg. The 137Cs and 239,240Pu pore water data show that there is preferential downward transport of 137Cs and that 239,240Pu does not have an active diagenetic chemistry and is not significantly mobile in these coastal sediments.