This cross-sectional study of reading,writing and mathematics skills in a total population of 589 children attending 4th grade in regular public schools showed that neuropsychiatric disorder was a strong predictor of poor performance, girls scored better than boys on language tests and some mathematics test, and immigrant children had similar results as native Swedish children on most tests. Sixty percent of boys with and 7% of boys without DAMP (Deficits in Attention,Motor control and Perception) or ADHD (Attention- Deficit/Hyperactivity Disorder) had substantial school difficulties. The rate of children requiring individualised special education measures was estimated at a minimum of 15%. This constitutes a major challenge to a society claiming to offer equal opportunities and participation for all children.