Sweden has become increasingly multicultural. In the year 2000, almost 25 per cent of the child and adolescent population was of foreign origin. Such a major change in demographics may lead to altered orthodontic treatment need in the community, with implications for planning appropriate levels of orthodontic resources. The aim of this study was to compare the frequency of malocclusion and orthodontic treatment need in 12- and 13-year olds of Swedish and immigrant background. The subjects, n = 493, were stratified into four groups according to family origin: (A) subject and both parents born in Sweden, and subject or at least one parent born in (B) Eastern Europe, (C) Asia, or (D) other countries. Registrations were based on available radiographs, patient records, and a clinical examination. Normative treatment need was based on a number of variables. Treatment need was expressed according to the dental health component (DHC) and aesthetic component (AC) of the Index of Orthodontic Treatment Need (IOTN). Group A exhibited the greatest space deficiencies and irregularities in the maxillary and mandibular anterior segments and also the greatest overjet. More primary molars had been extracted in groups B and C, with a positive correlation between early extraction of primary molars and retention of permanent successors. Self-assessed orthodontic treatment need, IOTN-AC, was highest in group A. For all four groups, the orthodontist's estimate of treatment need was significantly higher than the subjects' self-assessed need. This study confirms that, despite the change in demographics, variations in frequencies of malocclusion and treatment need among children of different cultural background are only minor and the overall orthodontic treatment need remains unchanged.