Primary immunodeficiencies are rare diseases, characterized by an increased susceptibility to infections. Early diagnosis and appropriate treatment are critical for reducing morbidity and mortality. Given the rarity of these diseases, the awareness of these disorders by physicians is often insufficient, leading to delayed diagnosis and inappropriate treatment which are the major causes of severe long term complications. In an attempt to address and resolve these problems an Italian Network on primary immunodeficiencies has been established with the aim to increase the awareness of these disorders among physicians and to provide the best clinical assistance to all patients on the national territory.