The aim of this controlled historical cohort study was to assess the validity of post-concussion syndrome in children. We identified 301 children aged 4-15 years who had sustained an isolated brain concussion, and another group of 301 children who sustained any other mild body injury excluding the head. Parents from both groups filled in standardized questionnaires containing questions about the health condition of the children: headache, neck pain, dizziness, malaise, fatigability, exercise or noise intolerance, irritability, weepiness, sadness, anxiety, nocturnal enuresis, tics, sleep disorders, memory or learning difficulties, hyperactivity, seizures, attention disorder, buzzing in the ears, subjective parental concerns about the child's health condition, and parental concerns about their child having a brain disorder. The severity of the complaints was rated on the Visual Analogue Scale. After the final exclusion, 102 pairs strictly matched by sex, age, and the date of trauma were analyzed. The differences of parental complaints about the health condition of their children between case and control groups were statistically insignificant for all symptoms, except parental concerns about their child having brain damage which were significantly higher in the case group. The likelihood of parental concerns about the possibility of their child having brain damage was 2.7 times higher in the case group. Headache, learning difficulties, and sleep disorders were significant variables predicting the concerns. These results question the validity of the post-concussion syndrome in children.