We report a study on the dielectric relaxation behaviour of samples of sodium carboxymethyl cellulose and its acid form covering the frequency range 20-10.rhlf.5.hlf. Hz and the temperature range 40-90°C. Treating the data in terms of an impedance formalism using the electrical modulus rather than admittance formalism using the complex dielectric constant revealed that two relaxation processes in NaCMC while its acid form, HCMC shows only one. The high frequency process in both NaCMC and HCMC is attributed to the reorientation of the carboxymethyl groups. These results suggest that the previous assumption of lacton formation in HCMC seems to be untenable. The lower frequency in NaCMC is due to a conductivity relaxation. The shorter relaxation time of the latter indicates that the transport of charge carrier requries the motion of the chain segment. The effect of the degree of substitution on the dipolar relaxation in NaCMC is also discussed.