Unsupported "free" nano-gamma-Fe2O3 is an active, stable, and reusable catalyst for selective oxidations of alcohols and olefins applying hydrogen peroxide as terminal oxidant. Catalyst activity and selectivity are controlled by tuning the particle size. The formation of a thin carbon-layer on the surface of the nano-iron oxide during the reaction permits for high catalyst stability. All catalysts were characterized by TEM, X-ray photoelectron spectroscopy (XPS), XRD, and EPR. (C) 2008 Elsevier B.V. All rights reserved.