The influence has been studied of the partial pressure of hydrogen (0-30 kPa) upon the coking rate of a Cr2O3/Al2O3 commercial catalyst during 1-butene dehydrogenation. Coke deposition has been analysed using a monolayer-multilayer reversible coke growth model (MMRC model). This model provides good fits to the experimental data, within the range of partial pressure of H-2 studied, and allows us to estimate the main kinetic parameters involved in the coking-deactivation process. The results obtained reveal a dual effect of hydrogen : competition against 1-butene for the active sites and the removal of coke precursors from the catalyst surface. Both effects diminish the coking rate as the H-2, partial pressure is increased.