A sequence of alternating periodic and chaotic current oscillations was found during the electrodissolution of a rotating copper disc in an acetic acid/sodium acetate buffer. The mixed-mode oscillations consist of combinations of large and small amplitude oscillations in peak current that were generated by incrementing the rotation rate of the copper electrode under potentiostatic control at 770 mV versus the saturated calomel electrode. Return maps of the chaotic intermediates were obtained and chaotic attractors were reconstructed in a three dimensional phase space using the method of time delays. The largest Lyapunov exponent was calculated to confirm the existence of deterministic chaos.