The electrical conductances of 0.001 M NdCl3, SmCl3, GdCl3 and DyCl3 solutions were measured in the temperature range 373-673 K at pressures up to 37.27 MPa, using a flow type electrical conductance cell. The cell constant was calculated by means of the measured conductance of five solutions of KCl, with concentrations range of 0.0001-0.002 M and the equivalent values calculated from Barthel equation at 298 K and was found to be equal to 0.111 cm(-1). By using the measured electrical conductance values, the specific conductance, sigma, and the equivalent conductance, Lambda, were calculated. The maximum electrical conductance was obtained in the sub critical region at approximate to 548 K in all cases. At this temperature, the electrical conductance was found to increase with the increase in the ionic radius from Dy to Sm. The electrical conductance of Nd was found to be smallest, which could be attributed to a higher ionic association. (C) 2002 Elsevier Science B.V. All rights reserved.