We investigated submarine landslides along the western margin of the Ulleung Basin in the East Sea using sparker, subbottom profiler, and multibeam echosounder data. The analysis of bathymetric data indicates numerous U-shaped scars that initiate at water depths of −600 m. The presence of large number of scarps in the source area suggests multiple failures rather than a single event. The individual scars are up to 60 m high and 4 km wide. Seismic data clearly image erosional headwalls and the basal sliding surface which is characterized by a prominent high-amplitude reflector. Chaotic-to-transparent seismic facies are seen immediately downslope of the headwall scarps; these chaotic facies represent landslide deposits of about 20 m in thickness. Earthquakes associated with tectonic activity were probably the primary triggering mechanism for these failures although other processes (i.e. gas charging and sea level fluctuations) may have acted as pre-conditioning factors.