The Raman spectra of D2O solutions of deuterated polyacrylamide, acetamide, propionamide, and butyramide were measured to investigate the self-association of amide groups. Factor analysis and the deconvolution technique were used for the analyses of Raman spectra of these compounds, and the C=O stretching band of the amide groups could be separated into three major peaks. One of the peaks corresponded to a nonassociated amide group, and the others were assigned to different types of self-associated amide groups. Nonlinear least-squares curve fitting suggested the presence of intramolecular hydrogen bonding within a coil of polyacrylamide in aqueous solutions.