A new C-8 prenylated 5,7-dimethoxycoumarin, omphamurrayone, was isolated from the leaves of Murraya paniculata var. omphalocarpa, and its structure was established as 5,7-dimethoxy-8-(3-methyl-l-O-isovaleryl-2-oxobutyl)-coumarin on the basis of spectroscopic evidence. Eight other coumarins were also obtained and identified as murralongin, isomurralonginol isovalerate, murrangatin, minumicrolin (murpanidin), coumurrayin, toddalenone, aurapten and toddasin. The chemosystematic status of M. paniculata var. omphalocarpa is briefly discussed with respect to the infraspecific differentiation of M. paniculata.