In this study, generalisation effects to day-care/school settings were examined in an outpatient clinic sample of 127 children aged 4-8 years treated because of oppositional conduct problems in the home with parent training (PT) and parent training combined with child therapy (CT) ("Incredible Years"). Before treatment all children scored above the 90th percentile on the Eyberg Child Behavior Inventory (ECBI) for home problems, and met criteria for a possible or a confirmed diagnosis of either an oppositional defiant (ODD) or a conduct (CD) disorder. Further, 83% of the children showed clinical levels of conduct problems both at home and in day-care/school before treatment. Although most children improved at home, the majority still showed clinical levels of conduct problems in day-care/school settings after treatment and 1-year later. Combined PT and CT produced the most powerful and significant generalisation effects across the treatment period, however these improvements were not maintained 1-year later for most areas. The results of the present study, therefore, underline the need to target conduct problems not only exhibited at home but also in day-care/school settings, and to develop strategies to maintain positive generalisation effects after treatment for this age and problem-group.