The fragment size distribution of glass spheres fractured under impact loading is modelled using a two-parameter Weibull distribution equation. The effects of impact velocity and impact angle on the fragment size distributions are assessed. The change in size distribution are explained with respect to the transition in the dominating failure mechanism. The threshold conditions for this transition are identified. A method of predicting the fragment size distribution based on Weibull parameters is also proposed. (C) 2004 Elsevier B.V. All rights reserved.