The depleted carbon isotope (δ¹³C) of benthic foraminifera was regarded as an important indicator of ancient cold methane seepage. In this paper carbon isotope analyses were carried out for 6 benthic foraminiferal species from 4 surface sediments with carbonate nodules in the southwestern area off Dongsha Islands, South China Sea. The authors consider that the depleted δ¹³C values with significantly larger variability observed in benthic foraminiferal species in the southwestern area off Dongsha Islands, SCS are possibly caused by cold seeping activity. And the negative excursion of carbon isotope in the living attached benthic foraminifera may indicate an active cold seepage existed in the studied area. Then, the authors suggest that the epibenthic D.semiungulata be used as a potential indicator of cold seepage in the SCS.