This article introduces the difference between biphasic and monophasic transcranial magnetic stimulation (TMS). Waveform and current direction determine the effectiveness of TMS in humans. The alternating use of mono and biphasic pulses as conditioning or test pulse has so far not been possible. Since pulses of different waveform or orientation cannot be applied through the same coil at an interval in the millisecond range, using two different coils could be a feasible approach. This article brings in the concept of repetitive TMS (rTMS). Although clinical relevance is lacking, there is plenty of interesting data available for rTMS. Both pulse configuration and current direction affect the modulation of corticospinal excitability induced by rTMS. The effects during rTMS may differ from those outlasting rTMS. Further studies are needed to confirm the histological and physiological basis for these differences, and to clarify their clinical relevance.