A novel vertical architecture for all-printed organic electrochemical transistors, based on poly(3, 4-ethylenedioxythiophene):poly(styrene sulfonate), realized on flexible substrates, is reported. The transistors are manufactured along both faces of plastic or paper substrates via connections are realized using laser ablation or simple punch through using a pin. Successful modulation of the electric current that flows between the two sides of the substrate is achieved using electrolyte-gating electrochemical modulation of the electronic charge transport of the bulk of the transistor channel. In addition to this, the transistors are exhibiting fast switching high ON/OFF current ratios.