A technique of measurement of thermal conductivity of solid materials by differential scanning calorimetry is presented. It concerns small samples having a diameter less than 8.0 mm, a height less than 2.0 mm and a low thermal conductivity. This method requires many samples with different heights which are heated in such a way that a calibration substance put on their top undergoes a first-order phase transition. The analysis of heat transfer of a such experiment predicts that the slope of the differential power during the transition is proportional to the factor 2 and inversely proportional to the sum of the thermal resistances. A measurement of the thermal conductivity of samples made of polytetralluoroethylene powder, compressed at the density of 2.10 +/- 0.03 g cm(-3), has been performed; the value obtained is 0.33 +/-0.02 W m(-1) K-1. Measurements of thermal conductivity of small metal hydride pellets are also presented. The precision of the measurements are on average 10%. (C) 2004 Elsevier B.V. All rights reserved.