A one-pot direct reductive amination of aldehydes with primary and secondary amines using Noyori's catalyst (eta (6)-arene)Ru(H)TsDPEN in neat HCOOH/NEt3 mixture has been developed. The catalyst formed in situ allows full conversion of aldehydes with high selectivities towards the desired amine products within hours or even minutes at room temperature. For aromatic aldehydes, both 5:2 and 5:3 HCOOH/NEt3 mixtures prove to be suitable reaction media, with the former affording higher selectivities while the latter leading to much faster reaction rates. For aliphatic aldehydes, the 5:3 HCOOH/NEt3 mixture gives much higher selectivities due to the minimal loss from aldol condensation. This method has great application potential for the synthesis of amine products given the mild conditions.