In the present work we investigated the conformations of some N-mono-substituted propanamides of general formula CH 3 CH 3 CONHR, wherein R is chosen from n-(C 1 -C 9 )alkyl, cyclo(C 3 -C 6 )alkyl, some branched (C 3 -C 6 )alkyl or phenyl. The amides were synthesised by the well known Schotten-Baumann reaction--acylation of the corresponding amines with propionyl chloride. On the basis of FTIR data for diluted solutions (concentrations below 10 - 3 mol dm - 3 ) of N-mono-substituted propanamides in carbon tetrachloride, chloroform, dichloromethane, or a 1:1.5 mixture of benzene and carbon tetrachloride the exact position of the N-H stretching band was established. For spectroscopic data the different conformational isomers were assigned and its structures unequivocally proven. These results are in good accordance with 1 H NMR and MS data.