Activation of dinitrogen (N-2, 78 %) and dioxygen (O-2, 21 %) has fascinated chemists and biochemists for decades. The industrial conversion of N-2 into ammonia requires extremely high temperatures and pressures. Herein we report the first example of N-2 and O-2 cleavage by a uranium complex, [N((CH2CH2NPPr2)-Pr-i)(3)U](2)(TMEDA), under ambient conditions without an external reducing agent. The N-2 triple bond breaking implies a U-III-P-III six-electron reduction. The hydrolysis of the N-2 reduction product allows the formation of ammonia or nitrogen-containing organic compounds. The interaction between U-III and P-III in this molecule allows an eight-electron reduction of two O-2 molecules. This study establishes that the combination of uranium and a low-valent nonmetal is a promising strategy to achieve a full N-2 and O-2 cleavage under ambient conditions, which may aid the design of new systems for small molecules activation.