The sensitive detection of free fatty acids was investigated by using H$_{2}$O$_{2}$-bis(2,4,6-trichlorophenyl) oxalate chemiluminescence system after monodansyl cadaverine labeling. Because dansvl moiety is well excited by this chemiluminescence system, monodansyl cadaverine was a prominent reagent to this system for the determination of free fatty acids. The cluent of 50mM tris-HCI buffer (pH 7.7)-acetonitrile (1:4, v/v) was run through TSK gel ODS 80 TM column. The reagent solutions were mixed with the eluent containing the monodansyl cadaverine derivative of fatty acids from the column. By this system, linolic acid was detected 50 fmol by injected amount.