More accurate signal assignment for H-1- and C-13-NMR spectra of aqueous solutions of polyamideamine-epichlorohydrin (PAE) resin and its related compounds was achieved by using distortionless enhancement of polarization transfer (DEPT) and C-H correlation spectroscopy (COSY) methods. On the basis of the assignment, we developed new methods to determine the content of four-membered azetidinium ring (AZR) and number-average degree of polymerization (DPn) of the repeating unit of PAE by using NMR. Degree of introduction of epichlorohydrin into polyamideamine chains at the initial stage was 75-80%, and the resultant AZR content per one repeating unit in the PAE sample prepared in this study was about 72%. DPn of the initial polyamideamine was 32, and this value decreased to about 18 during the PAE preparation process. (C) 2004 Wiley Periodicals, Inc.