['To compare the balance skills of children after mild traumatic brain injury (TBI) with that of noninjured children matched for age, sex, and premorbid level of physical activity.', 'Cohort study.', 'Pediatric trauma center.', 'Thirty-eight children aged 7 to 16 years (mean, 12.2+/-2.8 y) were recruited in each group. Children with mild TBI had a mean Glasgow Coma Scale score of 14.8 and were considered normal on a neurologic assessment at hospital discharge. Noninjured children were friends of those with mild TBI.', 'Assessments of balance were conducted at 1, 4, and 12 weeks after mild TBI and at corresponding time intervals for the controls.', 'The balance subtest of the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP), the Pediatric Clinical Test of Sensory Interaction for Balance (P-CTSIB), and the Postural Stress Test (PST) were used.', 'Over the time interval of the study, analyses of variance revealed that children with mild TBI performed significantly worse than the noninjured group on the BOTMP balance subtest (P<.001) and on the PST (P=.031), as well as on the eyes-closed conditions in the P-CTSIB tandem position (P=.05).'] Do children show decreased dynamic balance after mild traumatic brain injury?