This work demonstrates a novel fabrication approach based on the combination of screen and aerosol jet printing to manufacture fully printed organic electrochemical transistors (OECTs) and OECT-based logic circuits on PET substrates with superior performances. The use of aerosol jet printing allows for a reduction of the channel width to ≈15 µm and the estimated volume by a factor of ≈40, compared to the fully screen printed OECTs. Hence, the OECT devices and OECT-based logic circuits fabricated with the proposed approach emerge with a high ON/OFF ratio (103–104) and remarkably fast switching response, reaching an ON/OFF ratio of >103 in 4–8 ms, which is further demonstrated by a propagation delay time of just above 1 ms in OECT-based logic inverter circuits operated at a frequency of 100 Hz. All-printed monolithically integrated OECT-based five-stage ring oscillator circuits further validated the concept with a resulting self-oscillation frequency of 60 Hz. © 2022 The Authors.