Recurrent respiratory tract infections are a common reason for visits to primary care practitioners or hospital physicians. They are placed at the junction of several medical specialities: paediatrics, ENT, pneumology, allergology, immunology, infectiology. The great diversity of the laboratory tests requested and on the other hand the proposed treatments, are the consequences of the diversity of the patients encountered and the paucity of the evidence based-medicine studies in this setting. The dilemma is how to identify the child for which recurrent respiratory tract infections are the witness of underlying condition, without performing repeated medical examinations, laboratory tests and treatments for normal children for which immunologic development occurs normally. The essential tools are the history analysis, physical examination and few laboratory tests. The other questions are how to include, for these patients, influenza and pneumococcal vaccines in the immunization program and how to assess the benefit/risk ratio and the cost of surgical treatments. This paper presents the thought of an expert group trying to define the situations where biological tests or treatments are useful.