The transformation of cyclohexene on palladium catalysts can take place via two competitive processes: disproportionation and dehydrogenation. A study conducted over a broad temperature range revealed that disproportionation prevails at low temperatures and dehydrogenation at high temperatures. When the reaction develops under continuous-flow conditions (viz. in a tubular reactor connected online to a mass spectrometer), a transition temperature exists for each catalyst above which hydrogen is formed in detectable amounts. Metal catalysts are strongly deactivated during the transformation of cyclohexene. This led us to examine the process by performing thermal programmed experiments, desorptions and thermal oxidations, which showed catalyst deactivation in this process to be the result of surface adsorption of benzene and carbon deposition. Finally, desorption and subsequent oxidation were found to effectively regenerate the catalysts, which thus regained their initial activity.