A randomized, double-blind, placebo-controlled study (N01103, NCT00105040) evaluated behavioral and emotional effects of adjunctive levetiracetam (LEV) treatment in children and adolescents (4–16years old) with uncontrolled partial-onset seizures. Patients received adjunctive LEV 20–60mg/kg/day (n =64) or placebo (n =34) for 12weeks. The Achenbach Child Behavior Checklist (CBCL) and portions of the Child Health Questionnaire—Parent Form 50 (CHQ-PF50) were used to assess behavioral and emotional functioning at baseline and end of the treatment period. Worsening of the mean CBCL Aggressive Behavior score occurred for LEV but not placebo, leading to similar results for Externalizing Syndromes and Total Problems (all P <0.05 vs placebo). The change in the CBCL Activities Competence score favored LEV (P <0.05). These results are in line with the known safety profile of LEV.