Echo character recorded on Chirp sub-bottom sonar data from o¡shore of SW Taiwan was analysed to examine and compare the sedimentary processes of adjacent passive and active continental margin settings. Sea£oor echoes in the study area are classi¢ed into four types: (1) distinct echoes, (2) indistinct echoes, (3) hyperbolic echoes and (4) irregular echoes. Based on the mapped distribution of the echo types, the sedimentary processes o¡shore of SW Taiwan are di¡erent in the two tectonic settings. On the passive South China Sea (SCS) margin, slope failure is the main process on the upper continental slope, whereas turbidite deposits accumulate in the lower continental slope. In contrast, the submarineTaiwan orogenic wedge is characterized by ¢ll-and-spill processes in intraslope basins on the upper slope, and mass-transport deposits are observed in the canyons and on the lower Kaoping slope.This di¡erence is largely caused by the huge in£ux of terrigenous sediments into the submarineTaiwan orogenic wedge compared with the passive SCS continental margin. In the latter, loading and movement of theTaiwan orogenic wedge has had a signi¢cant e¡ect on the sea£oor morphology and has triggered retrogressive failures. Gas hydrate dissociation may have enhanced the slope failure processes at some locations.