Aluminum nanopowders, because of their larger surface area, can increase the burning rate of propellants. It has been suggested that the powders could also enhance the detonation properties of certain explosives. For these reasons, an experimental study was undertaken to compare the performance of nanometric and micrometric aluminum in various explosives. No enhancement of performance was found in plastic-bonded explosives. In fact, a reduction of the detonation velocity was found in plastic-bonded explosives that are based on an energetic binder system. No increase of the detonation velocity was found in mixtures of aluminum and either Composition B or Ammonium Nitrate Fuel Oil, but a small increase in the heat of detonation was measured. The mixture of TNT and nano-aluminum demonstrated higher detonation velocities and heats of detonation. The increase was higher at small charge diameters. Nanometric aluminum was shown to reduce the critical diameter of such mixtures, and it is concluded that the nano-aluminum reacts faster than regular micron-size particles in TNT/Al compositions.