Bacterial amines were examined by gas chromatography/mass spectrometry. Under electron impact all trifluoroacetamides exhibited peaks at m/z 69 due to [CF3]+. Many trifluoroacetamides also showed peaks at m/z 97 corresponding to the [COCF3]+ ion fragment. The spectra of n-alkyl and aralkyl trifluoroacetamides were consistent with the spectra and their interpretations in the earlier literature. Molecular ions were of low abundance for all alkyl trifluoroacetamides having alkyl chains longer than two carbon atoms. Chemical ionization gave molecular weight information in all cases. Most peaks observed were molecular addition products, e.g. [M + H]+ and [M + NH4]+. Application of chemical ionization mass spectrometry to analysis of bacterial amines revealed the production of beta-phenylethylamine, n-decylamine, 1,4-diaminobutane and 1,5-diaminopentane by Clostridium histolyticum; whereas both Clostridium bifermentans and Clostridium oedematiens produced beta-phenylethylamine. The latter organism also produced a peak with a retention time similar to that of an authentic amylamine derivative.