Catalytic hydrogenations are important and widely applied processes for the reduction of organic compounds both in academic laboratories and in industry. To perform these reactions in sustainable and practical manner, the development and applicability of non-noble metal-based heterogeneous catalysts is crucial. Here, we report highly active and air-stable nickel nanoparticles supported on mesoporous silica (MCM-41) as a general and selective hydrogenation catalyst. This catalytic system allows for the hydrogenation of carbonyl compounds, nitroarenes, N-heterocycles, and unsaturated carboncarbon bonds in good to excellent selectivity under very mild conditions (room temperature to 80(degrees)C, 2 to 10 bar H-2). Furthermore, the optimal nickel/meso-silicon dioxide catalyst is reusable (4 cycles) without loss of its catalytic activity.