The paper describes the bioassay-guided isolation, structure elucidation and anticancer evaluation of five flavonoids (-)-liquiritigenin (1), (-)-neoliquiritin (2), isoliquiritigenin (3), isoliquiritin (4) and formononetin (5) from the twigs of Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry. The structures were elucidated based on 1H, 13C NMR, comprehensive 2D NMR, MS analyses and comparison with previously reported spectral data. Compounds 1 and 3 were demonstrated to be inhibitory in vitro against NCI-H187 (small cell lung cancer) with IC50 values of 30.1 and 16.6 μg mL-1, respectively. The isolates were non-cytotoxic to Vero cells (African green monkey kidney). U radu je opisana izolacija, određivanje strukture i antitumorsko djelovanje pet flavonoida: ()-likviritigenina (1), ()-neolikviritina (2), izolikviritigenina (3), izolikviritina (4) i formononetina (5) iz plodova biljke Jacaranda obtusifolia H. B. K. ssp. rhombifolia (G. F. W. Meijer) Gentry. Strukture su određene na temelju 1H, 13C NMR, 2D NMR, MS i usporedbom s ranije objavljenim spektroskopskim podacima. Spojevi 1 i 3 imaju inhibitorni učinak in vitro na tumorsku staničnu liniju raka pluća NCI-H187 (IC50 vrijednost 30,1, odnosno 16,6 μg mL1). Izolirani flavonoidi nisu citotoksični za Vero stanice (bubrež ne stanice afričkog zelenog majmuna).