The aim of this study was to identify risk factors for the occurrence of challenging behavior along with the specific topographies of challenging behavior shown by a sample of children with autism spectrum disorder in Ireland. The occurrence of challenging behavior was examined in comparison with the following variables: gender, age, level of intellectual disability, type of intervention and the hours of intervention being received. The Behavior Problems Inventory - 01 was used to gather data for 157 participants. Results indicated that 64.3% (n = 101) of the participants showed challenging behavior, with a high co-occurrence across categories of behavior. The present study found no correlation between age and gender and the presence of challenging behavior. Findings in relation to level of intellectual disability, type and hours of intervention received are discussed. (C) 2008 Elsevier Ltd. All rights reserved.