The low frequency (100 kHz) dielectric behaviour at room temperature of methanol/carbon tetrachloride solutions over the whole composition range is compared with the ideal case as described in the framework of Onsager theory. We find negative deviation at high methanol dilution and an opposite behaviour at high concentration. While the formation of cyclic methanol clusters is able to justify the observations at high dilution, association of carbon tetrachloride with chain end methanol is proposed as a possible mechanism able to explain the positive deviations from ideality found at high concentrations. (C) 2003 Elsevier B.V. All rights reserved.