The epidemiology of anxiety traits was examined in a large sample of Italian preadolescent children, and 3,479 Italian nine-year-old subjects were enrolled. Anxious traits were observed in 10.5% of children. No significant gender differences were found, but children of separated couples presented a relative risk for anxious traits that was 50% higher, than children of cohabiting or married parents. Moreover, large families (more than 4 members) with a stay-at-home mother were also associated with anxiety in the offspring. Currently, this is the first study carried out in a large sample of preadolescent children, all of the same age.