Herein, we report a complete additively manufactured (AM) electrochemical sensing platform. In this approach, a fully AM/3D-printed electrochemical system, using a conventional low-cost 3D printer (fused deposition modeling) fabricating both the conductive electrodes and the nonconductive/chemically inert electrochemical cell is reported. The electrodes (working, counter, and pseudo-reference) are AM using a conductive fused-filament comprised of a mixture of carbon black nanoparticles and polylactic acid (CB/PLA). AM components partially coated with silver ink presented a similar behavior to a conventional Ag/AgCl reference electrode. The performance of the AM working electrode was evaluated after a simple and fast polishing procedure on sandpaper and electrochemical activation in a NaOH solution (0.5 mol L-1). Following the electrochemical activation step, a considerable improvement in the electrochemical behavior (current intensity and voltammetric profile) was obtained for model analytes, such as dopamine, hexaammineruthenium(III) chloride, ferricyanide/ferrocyanide, uric acid, and ascorbic acid. Excellent repeatability (RSD = 0.4%, N = 10) and limit of detection (0.1 μmol L-1) were obtained with the all complete AM electrochemical system for dopamine analysis. The electrochemical performance of the developed system (after simple electrochemical activation of the working electrode) was similar or better than those obtained using commercial glassy carbon and screen-printed carbon electrodes. The results shown here represents a significant advance in AM (3D printing) technology for analytical chemistry.