In order to assess bicycle helmet effectiveness in preventing head injury in children, we performed an international qualitative and systematic review using the criteria of the French Health Accreditation and Evaluation National Agency (ANAES) developed for recommendations in clinical practice (formulation of a question, judgment criteria, collecting references, quality analysis, interpretation of results). Two hundred and thirty-four papers dealing with the subject were identified through a MEDLINE search. Two hundred and fifteen of them were eliminated as they did not meet selected criteria. Four were eliminated because of language criteria. On the 14 meeting all selection criteria, five were judged satisfactory according to qualitative criteria. All five conclude in favor of the effectiveness of the bicycle helmet even when taking bias into account. The real protection afforded by wearing a bicycle helmet militates in favor of its habitual use.