The purpose of this report was to estimate the association between children's trouble sleeping and anxiety/depression at ages 6 and 11, cross-sectionally and prospectively. Data come from a study of the psychiatric sequelae of low birth weight (LBW: <2500 g). LBW and normal birth weight children were randomly selected from the 1983-1985 newborn lists of an urban and a suburban hospital. Eight hundred and twenty-three children participated at age 6 and, of those, 717 (87.1%) participated at age 11. Achenbach's Child Behavior Checklist (CBCL) and the Teacher Report Form (TRF) were used to obtain ratings of psychiatric problems. The CBCL asked if the child had trouble sleeping during the past 6 months. Children with trouble sleeping had significantly increased odds of anxiety/depression based on mothers' reports (OR=6.9, 95% CI 4.1-11. 4) but not teachers' reports (OR=1.1, 95% CI 0.4-2.7). There was a greater association between sleep and depression at age 11 than at age 6, and among suburban than among urban children. These findings remained when adjusted for birthweight, sex, and mother's history of major depressive disorder. Profile analysis indicated a stronger association of trouble sleeping with anxiety/depression than other psychiatric problems. The association of trouble sleeping at age 6 with incidence of depression at age 11 was not statistically significant (suburban children RR=2.22, 95% CI 0.53-9.23; urban children RR=0.92, 95% CI 0.20-4.18).