Material comminution is one of the typical processes present during the injection abrasive water jet generation inside the mixing chamber and the focussing tube of the abrasive water jet cutting head. The determination of an extent of changes in the size of particles induced in the cutting head is the main objective of this contribution. Knowledge of the particle size at the exit from the cutting head is necessary for studying of the subsequent processes, e.g. the impingement of water jet with industrial mineral particles on a solid-state target or collision of such water jet with liquid barrier or opposite flowing jet of the same type. (C) 2010 Elsevier B.V. All rights reserved.