Results are presented of a study of the (normalized) complex dielectric coefficient, and related parameters, of unidirectionally frozen artificial sea ice having salinities from 4 to 20‰. The frequency dispersion was investigated between 20 Hz and 100 MHz at temperatures from −35° to −12.5°C. An unusual measurement cell, which becomes incorporated into the ice as it forms, is described and justification offered for its use. The frequency dispersion of the real part of the dielectric coefficient may be considered in three parts. Large values (105to 106at −15°C, and 103to 104at −35°C) were observed at 20 Hz, falling slightly more rapidly than (frequency)−1up to 5 kHz. Between 5 and 500 KHz most curves exhibited a distinct downward concavity (which was more prominent at lower temperatures), values dropping from between 103and 104to the order of 102over this range. At higher frequencies the rate of decrease was smaller, values of 10 or less being observed at 100 MHz. Loss factors (values at 20 Hz: 106to 107at −15°C, and 104to 105at −35°C) in most cases decreased approximately as (frequency)−1over most of the frequency range. Loss tangents, which were slightly larger at higher temperatures, were of order 10 below 1 MHz, dropping to less than 1 above 10 MHz. The curves for this parameter exhibited two temperature‐dependent maxima. The electrical properties changed most rapidly with temperatures near −23°C, the NaCl deposition temperature.