We reviewed the medical records of the 118 adolescent detainees which had at least one consultation by a psychiatrist at the prison health facility during 2007. General practitioners used the International Classification of Primary Care (ICPC-2) for recording health problems. Psychiatrists used the International Classification of Diseases (ICD-10) for making psychiatric diagnoses. The concordance between the mental health assessment done by general practitioners using the ICPC-2 and the diagnoses proposed by psychiatrists was globally satisfying. The five most frequent ICD categories (conduct disorder, drug abuse, alcohol abuse, personality disorder, adjustment disorder) encompassed the most frequently reported ICPC-2 psychological symptoms. Several associations between psychological symptoms and socio-demographic characteristics were observed. Apart from providing a description of the mental health of adolescent detainees in one of Switzerland's largest detention centre for minors, results suggest that general practitioners can adequately identify frequent mental disorders in such contexts.