Hydrogenation of chlorosilane was achieved in acetonitrile using NaBH4, a safe and easy-to-handle reagent. This reaction converted Si–Cl portion(s) in organosilanes into Si–H portion(s) without hydrogenation of cyano, chloro, and aldehyde groups on an alkyl substituent of the Si reagents. In addition, the Si–Cl/Si–H exchange reaction was applicable to dichlorodisilane without Si–Si bond cleavage.