Probation officers and others who work with young offenders often challenge or confront their clients in relation to pro-criminal comments and criminal behaviour. There is, however, very little research that can inform practitioners about which forms of challenging most effectively engage young people. This study examines the use of challenging by youth justice workers in New South Wales, Australia. Researchers observed and audiotaped 116 interviews between youth justice workers and their clients with a view to examining the nature of challenging used by workers and the response of young people to different forms of challenging. Qualitative and quantitative findings indicate that the clients were more positively engaged by, and responsive to, challenging that was exploratory, non-blaming, and accompanied by positive reinforcement of their strengths. Excerpts taken from the interviews provide examples of high- and low-level use of the skill of challenging.