An efficient method to prepare nitriles from aldehydes using hexamethyldisilazane (HMDS) as the nitrogen source has been developed. The reactions were performed with 2,2,6,6-tetramethylpiperidine l-oxyl (TEMPO) as the catalyst, NaNO₂ or TBN as the co-catalyst, and molecular oxygen as the terminal oxidant under mild conditions. A variety of aromatic, heteroaromatic, aliphatic and allylic aldehydes could be converted into their corresponding nitriles in good to excellent yields.