Lupane- and oleanane-type triterpene acid derivatives reacted with nicotinic- and isonicotinic-acid hydrazides to synthesize C-17 and C-20 acylhydrazides, dehydration of which formed the corresponding 1,3,4-oxadiazole derivatives. Cytotoxicity studies of the obtained compounds showed that conjugates of oleanolic acid with acylhydrazide and 1,3,4-oxadiazole fragments (bound to a pyridin-4-yl or pyridin-3-yl substituent) on the triterpene C-17 atom were active. The most active compound 3-oxo-28-nor-17-{2 '-[1 ',3 ',4 '-oxadiazol-5 '-(pyridin-4-yl)]yl}olean-12(13)-ene inhibited the growth of leukemia HL-60(TB), RPMI-8226, SR, colon (HCT-116), kidney (A498), and prostate cancer cells (PC-3).