A theoretical and experimental analysis of the oxidation of aluminum nanoparticles is presented. The modeling of the oxidation is based on a modified Mott-Cabrera model. Mass and heat transfer, both at individual particle level are implemented. An investigation of the final oxide layer in the passivation process is carried out for nanometer sized particles. The model predicts the effect of the particle's radii on the oxide layer growth and on the particle's temperature. A 2 nm particle reaches a passive layer of 8 angstrom in almost 2000 s increasing its temperature from 300 K to a peak of almost 500 K. Parametric analysis on the influence of temperature and partial pressure of oxygen are performed. Thermo-gravimetry measurements are used and compared to the model's results. Good agreement between the model and the experimental results, especially at low temperatures, makes it possible to estimate and devise a strategy for efficient and safe passivation of aluminum nanopowders. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.