The temperature-dependent characteristics of an InP/InGaAs superlattice-emitter resonant-tunnelling bipolar transistor have been studied and demonstrated. Due to the use of a five-period InP/InGaAs superlattice, the RT effect is observed at cryogenic temperature. In addition, the temperature-dependent dc characteristics of the studied device from room temperature to 398 K are reported. Dc current gain remains at an approximately constant value over the measured temperature range. The temperature coefficients of base-emitter and base-collector turn-on voltages are -2 and -3 mV K^-1, respectively. The ideality factors of base current (n_B) and collector current (n_C) exhibit negative temperature coefficients. n_B≈1 indicates that the bulk base recombination current component dominates the whole base current as the temperature is increased.