The effects of emitter‐base junction gradation, mobility gradients, and electric field gradients on the injected minority‐carrier density distributions in the base region of narrow‐base transistors are analyzed. It is shown that the collector current of transistors having a graded emitter‐base junction deviates from the ideal characteristics. The factors which contribute to this departure are analyzed in this paper. It is also shown that the emitter‐base forward bias voltage affects the transit time significantly in narrow‐base transistors, even when high injection level conditions are absent.