An efficient and simple palladium-catalyzed approach for the synthesis of aryl ketones from low-cost nitriles and arylhydrazines using molecular oxygen (O<sub>2sub>) as sole oxidant via C–N bond cleavage is reported. Various aryl ketones were synthesized in moderate to good yields under mild conditions. A possible mechanism involving the Pd<sup>IIsup>/Pd<sup>0sup> catalytic cycle process is depicted, and a cationic palladium intermediate was detected by ESI-MS.