There is a substantial literature reporting the co-occurrence of maternal depression and child behaviour problems. Behavioural interventions have proven efficacy in the treatment of conduct problems, and a number of studies have reported gains in parental mental health following parent training. The mechanisms by which this is achieved are not clear, but it is likely that interventions that include parent training in observation skills and exposure to success will impact on both the child's conduct problems and maternal depression. This paper reports on the outcomes of two treatments for children with severely disruptive behaviour, the standard treatment offered by a Child and Adolescent Mental Health Service, and an intensive parent training intervention. It was predicted that the more specific skills training in the intensive treatment would make improvements in maternal health and child behaviour more likely. Significant overall improvements were found in measures of child behaviour, parental practices and maternal mental health. A correlation emerged between the improved child behaviour and the improved parenting strategies. Significant improvements for the intensive treatment group were seen on every measure. Significant improvement in the measure of maternal mental health contrasted with little change for the standard treatment group.