3D printing technology has emerged as a platform for rapid prototyping of materials and devices for an extended range of applications. Composite polymer electrodes represent an attractive form of printable materials with task-specific tunability. However, there are currently limited materials available as polymeric-composite electrodes with desirable conductivity and robustness to serve as electromaterials. Herein, we report the fabrication of robust and flexible multilayer 3D printed graphene/polycaprolactone composite electrodes consisting of 10 wt% graphene. This represents a new class of printable biodegradable eco-friendly composite electrodes, with inherent conductivity for the electrochemical studies. The electrode biocompatibility is demonstrated by the electrochemical response derived from the diatom microalgae grown on the graphene/polycaprolactone substrate. We propose that the prepared conductive-biodegradable graphene/polycaprolactone composite can also potentially serve as a scaffold for electrical stimulation in promoting tissue formation for regenerative medicine, as well as bioelectronic applications.