Dielectric relaxation in the comb-like polymer poly-N- n-octadecylmethacrylamide has been investigated and the results obtained have been compared with data from poly-N- n-octadecylacrylamide with the aim of studying the effect of the nature of the α-substituent, the number of hydrogen bonds and the conformational structure on intramolecular motion. It has been shown that the relaxation time and the activation energy in the region of the dipole relaxation connected with the local mobility of the amide group are not dependent on the factors mentioned and are determined by the interaction between side chains. It is characteristic of both polymers that there is no clearly expressed dielectric α-transition in the region of the glass transition but an intense relaxation process is observed in the rubbery state of the polymers. Its cause is attributed to the specific effect of hydrogen bonds.