The flow distribution in the rectangular channel of a pilot-scale electrolytic cell was observed using an imperfect tracer-pulse injection technique in order to study residence time distribution (RTD), back-mixing effects, and velocity profiles of the electrolyte liquids within the cathode compartment. The electrolytic cell was operated under cold flow and at process conditions. While residence time studies performed in a vast number of applications are mainly based on classical conducto-metric measurements, alternative measurement methods have to be applied in electrochemical systems. Hence, this study deals with the investigation of RTD using laser-induced fluorescence (LIF) visualization. Back-mixing effects of the electrolyte are quantified using the axial dispersion flow model. RTD studies for the overall cell as well as velocity profile analysis for selected individual regions are conducted. Additionally, the effects of the nonstabilized membrane and of the membrane-stabilizing spacer grid are investigated.