The methanation of carbon monoxide on the commercial Ni/SiO2 catalyst was studied experimentally under transient reaction conditions. Two types of concentration changes of the reactor feed were used : (i) step-changes for the investigation of elementary system dynamics, and (ii) forced feed composition cycling for examination of the effect of the periodic feed modulation on the time-average reaction rate. The experiments were performed in a laboratory flow microreactor in the temperature range between 458 and 538 K. It has been found that forced feed composition cycling significantly increases the reaction rate for any composition of reactor feed including composition leading to the highest steady-state rate. The enhancement of the methanation rate is caused by massive deposition of carbonaceous intermediates on the catalyst surface. Those deposits are unreactive under steady-state conditions due to the blocking of active sites for adsorption of hydrogen by CO but highly reactive during feed concentration cycling for alternating between GO-rich and GO-lean feeds.