This paper presents a new method dedicated to thermal conductivity measurement of low-density insulating materials. The three layers experimental device (brass/sample/brass) and the principle of the measurement based on a pulsed method are presented. The three-dimensional modelling of the system is used for a sensitivity analysis. The estimation method is described and applied to experimental measurements carried out at atmospheric pressure and under vacuum. We conclude that the thermal conductivity is estimated with a precision better than 5% and that the precision of the thermal diffusivity estimation depends on the density of the material. (C) 2008 Elsevier Ltd. All rights reserved.