The complex permittivity spectra of dimethylene chloride with N-methylformamide have been determined at 10, 15,20 and 25 degrees C using time domain reflectometry (TDR) for 11 different concentrations of the system. The complex permittivity spectra shows that the dielectric constant is high in the lower frequency region and decreases with an increase in frequency and the peak of dielectric loss curves shifted toward higher frequencies when the temperature increases in the system. The dielectric parameters viz. static dielectric constant (epsilon(o)) and relaxation time (tau) have been obtained by the least squares fit method with Debye model. For temperature range, considered here, the dielectric constant and relaxation time increase with increasing the mole fraction of n-methylformamide. The excess permittivity and excess inverse relaxation time are found to be negative in the system. (C) 2014 Elsevier B.V. All rights reserved.