The end-Permian mass extinction is associated with a global perturbation in the carbon isotopic composition of carbonates and organic matter, but such changes are not well documented from pelagic deep-sea sediments. One of the most continuous pelagic deep-sea Permian/Triassic boundary (PTB) sections, the Am-2 section, is exposed in the accretionary complexes of Japan. New data for organic carbon isotope ratios (delta(13)C(org)) were obtained from 36 samples from section Am-2. The delta(13)C(org) excursion curve exhibits a negative shift of 2.0 parts per thousand in the low-latitude, pelagic Panthalassic Ocean at the end of the Permian, which coincides with a radiolarian extinction. The delta(13)C(org) values of pelagic, deep-sea Panthalassic sections and those of shallow-water sections from Panthalassic seamounts exhibit a smooth, negative shift that lacks temporary increases like those reported from Paleotethyan PTB sections. Absence of temporary delta(13)C(org) increases at the PTB in Panthalassa may reflect less algal and bacterial blooming in pelagic Panthalassa compared to the shallow-water Paleotethys. (C) 2010 Published by Elsevier B.V.