A solvent and concentration study of three cis lactams in the i.r. and near-ix. has led to a partial revision of amide group combination band assignments for two of the lactams, permitting differentiation between the strained ring and larger ring cis lactams. The near-i.r. spectra of the lactams proved to be characterized primarily by overtone and combination bands attributable to the non-hydrogen-bonded amide grouping, inasmuch as conditions which favor inter-amide association result in the disappearance of bands without concomitant replacement by distinctive bands assignable to hydrogen-bonded molecules, and the spectra become very featureless. This contrasts with the spectral behavior of trans open-chain secondary amides which reveal clearly defined contributions from 2~~" and (vNH + amide II) and other combination modes predictably assignable to hydrogenbonded molecules. The hydrogen-bonding studies using the near-i.r. thus provide a way to distinguish between compounds containing cisand trans-configured secondary amide groupings. The results proved to be consistent with the symmetry property differences between the associated forms of the two classes of amides and will be useful for application of the near-i.r. as a quantitative probe for hydrogen-bonding effects within these functional group classes.