In this paper a new electrothermal compact macromodel of the monolithic switching voltage regulator MC34063A for SPICE is proposed. This macromodel, valid for the transient analysis, is composed of two essential parts: the electrical model consisting of the most important fundamental blocks as: the oscillator, the comparator, the RS flip-flop, the output stage as well as the lumped thermal model. The correctness of the macromodel is verified experimentally. The values of the macromodel parameters are determined from the measurements and the catalogue data. Some of the calculated characteristics are compared with the measuring results.