The catalytic hydrogenation of nitriles represents an atom-economic and valuable route to amines. In the present study, the ruthenium-catalyzed hydrogenation of various organic nitriles to give primary amines has been examined in detail. Straightforward ruthenium complexes modified by cheap and widely available triphenylphosphine allow for the efficient and general reduction of various aryl, alkyl, and heterocyclic nitriles. By using a practical in situ catalyst composed of [Ru(cod)(methylallyl2)] and PPh3, excellent yields and chemoselectivity were achieved. Moreover, the catalyst system displays broad functional group tolerance.