Eighteen volatile compounds in cod fish have heen identified hy their mass spectra and gas chromatographic retention times. Volatile compounds were vacuum distilled at 35°C from fresh cod fish and from samples stored for 7 and 14 days. Fractions collected in traps immersed in ethyl alcohol- Dry Ice or liquid nitrogen were separated on aββoxydipropionitrile column by programmed cryogenic temperature gas chromatography. The eflluent from the column was split to a flame ionization detector and to a molecular separator leading to a fastscanning mass spectrometer; this arrangement permitted simultaneous recording of gas chromatograms and mass spectra. The following compounds have not been previously reported in the literature for cod fish: carbon disulfide, methylene chloride, chloroform, benzene, toluene, methyl propyl ketone, diethyl ketone, and methyl vinyl ketone. Compounds which were identified only in stored samples were triinethylamine, propionaldehyde, butyraldehyde, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, and methyl vinyl ketone. No attempt has yet been made to determine the significance of these compounds to decomposition.