Among asylum-seeking children aged 4-16 years living in the asylum centres managed by the Danish Red Cross in 2006, we investigated mental health in relation to length of stay and number of relocations. Mental health was evaluated using the Strengths and Difficulties Questionnaire (SDQ). We found that children who had been asylum-seeking for more than one year had an increased risk of having mental difficulties (odds ratio 5.5; 95% confidence interval 1.8-16.3); four or more relocations in the asylum system were also associated with a higher risk of mental problems (odds ratio 3,0; 1,4-6,7).