Ruthenium‐catalyzed hydrosilylation of aldehydes with hydrooligosilanes is reported. Among the examined ruthenium catalysts, RuH2(CO)(PPh3)3 gave the best results. The reactions proceed with the Si–Si bonds preserved to afford the corresponding alkoxyoligosilanes in good yields. A series of aryl aldehydes with an electron‐withdrawing group is applicable, whereas those with an electron‐donating group are not suitable for the reaction. Mechanistic considerations suggest that the key points for the preservation of the Si–Si bonds are the formation of zero‐valent ruthenium species and the efficient coordination of the aldehyde to the ruthenium center prior to the oxidative addition of the Si–H bond.