In this paper the problem of measuring the thermal resistance of silicon semiconductor devices including p–n junction – available for a user, is considered. The values of the thermal resistance given in the catalogues rarely correspond to the real conditions of device cooling. Therefore, the value of the thermal resistance has to be obtained from measurements. In the paper a new convenient method of the measurements of the thermal resistance of silicon semiconductor devices with p–n junctions, based on the measurements of d.c. current–voltage characteristic of the junction and the estimation of the model parameter values with the use of SPICE MODEL EDITOR – software, is presented. The results of the measurements obtained with the new method are compared to the standard pulse method. The proposed method can be applied for such devices as: p–n diodes, power MOS transistors, Darlington transistors as well as IGBTs having the antiparallel diodes.