A genuine dammarane-glycoside, named as ginsenoside $ Rs_3$, was isolated from the MeOH extracts of Korean red ginseng (Panax ginseng C.A. Meyer) through repeated silica gel column chromatographies and its chemical structure was determined as (20S)-protopanaxadiol $3-O-[6^{11}-O-acetyl-{eta}-D-glucopyranosyl (1{ ightarrow2)-{eta}-D-$glucopyranoside on the basis of several spectral and physical evidences including HMBC and FAB-MS.