Phytochemical study of the phytoalexins from Artocarpus heterophyllus stem bark led to the isolated two prenylated flavones, artonin A and cycloheterophyllin from toluene extract and one Diels-Alder type adduct of chalcone derivative, artonin D from methanol extract. The structures of all of these isolated compound were determined by extensive spectroscopic studies, including comparison of their UV, IR, MS and NMR properties with previously reported data.