The attrition propensity of used and fresh vanadium phosphorous oxide (VPO) catalyst subjected to mechanical stress in a gas cyclone and in a bubbling-fluidized bed with and without submerged gas jet has been investigated. Attrition models for the investigated sources of attrition have been adopted from literature. The attrition tests confirmed the relationship between the operating conditions and the steady-state attrition rates under abrasion conditions. The material specific attrition rate constants for the three sources of attrition have been determined. These constants were compared with those measured for other catalyst materials in previous attrition tests. It is found, that the investigated VPO catalyst has a low attrition propensity comparable to FCC-catalyst, when subjected to mechanical stress in gas cyclone and in fluidized bed with submerged gas jet. The attrition rate constant of the VPO catalyst subjected to mechanical stress in the bubbling-fluidized bed seems to be slightly higher than those measured for FCC-catalysts. However, the deviation is in the range of the experimental error. In agreement with previous findings for other catalysts the cyclone attrition rate constant for fresh VPO catalyst is higher than for used catalyst. (C) 2009 Elsevier B.V. All rights reserved.