A chemical quality index of canned tuna was established for estimating the extent of decomposition in fresh tuna prior to canning. Histamine has frequently been used as such an indicator but by itself it has not always proved useful. The relationship of 5 amines (histamine, putrestine, cadaverine, spermine and spermidine) was studied to generate a chemical index of tuna decomposition. The amines were extracted from authentic pack and commercially prepared canned tuna samples. The dansyl derivatives were formed and determined by reverse phase, linear gradient elution, high pressure liquid chromatography. An index was developed from the individual amines and the resulting chemical indices scores compared favorably to organoleptic and authentic pack value scores.