Bioassay-directed fractionation of a methanolic extract from the seeds of Draba nemorosa (Brassicaceae) led to isolation of a new flavonol glycoside, drabanemoroside (5, kaempferol 3-O-${alpha}$-L-rhamnopyranosyl-(1${ ightarrow}$2)-${alpha}$-L-arabinopyranose) along with four known flavonoid derivatives (1-4), four cardenolide glycosides (6-9). Kaempferol glycosides 2 and 5 showed strong cytotoxicity against human small lung cancer cell line A549 and melanoma SK-Mel-2 with an $IC_{50}$ of 0.5 ${mu}g/mL$ and 1.9 ${mu}g/mL$, respectively. Cardenolide glycosides 6-9 showed potent cyto-toxicity (A549) in the range of 0.01-0.032 ${mu}g/mL$. Their structures were characterized based on spectroscopic data (2D NMR, HRTOFMS, IR, and UV) and comparison of literature values. The carbohydrate units were also confirmed by comparing the hydrolysate of 5 with authentic monosaccharides.