The outcomes of a new universal program aimed at preventing depressive symptoms and disorders in 8- to 9-year-old children are presented. The Positive Thinking Program is a mental health promotion program based on cognitive and behavioural strategies. It is designed to meet the developmental needs of children in the middle primary school Years 4 and 5. Four state primary schools were randomly assigned to receive the program implemented by psychologists or to a control condition involving their regular Health Education curriculum. Seventy-two children participated in the intervention condition and 48 children in the control condition. Children completed measures of depressive and anxiety symptomatology, depressive disorders, and attribution style. The intervention was associated with reductions in depressive symptoms and more positive attributions at post-intervention. Compared to the control group, there was a lower prevalence of depressive disorders at posttest and fewer intervention group children developed a depressive disorder at a 9-month follow-up.