An improved DC parameter-extraction methodology for bipolar transistors is presented. The method uses a new step-by-step strategy based on measurements made under two saturation conditions only: zero voltage and zero current. This method minimises the self-heating effects without using pulsed techniques, and it is suitable for medium-power devices. Special emphasis has been placed on the determination of resistive parameters. The proposed method fits better the experimental data than the parameterextraction methodologies in use today. The relative r.m.s. error decreases from a value higher than 10% to 1% at high current levels.