This study investigated the effectiveness of cognitive self-management training as an adjunct to the behavioural management of childhood obesity. Twenty-seven overweight children aged 7-13 years were randomly assigned to either behavioural management plus relaxation placebo or a combined behavioural-cognitive self-management approach. Evaluations following the eight treatment sessions revealed a significant reduction in percentage overweight for children in both experimental groups and improvements were maintained at 3- and 6-month follow-ups. Both conditions were also effective in reducing the number of high-risk foods consumed. No difference in outcome was found between treatments at the post-treatment assessment or 3- and 6-month follow-ups. Although a reduction in percentage overweight of around 9% was found for both procedures, subjects in general remained considerably overweight.