The selective deficit of IgA is the most frequently acquired immunodeficiency. It is important because of this and the variability of the clinical presentation, which might be non-symptomatic or simply show several clinical features. The prognosis depends on the associated clinical affliction. There is no substitute treatment for this immunodeficiency, in which the immunoglobulins administration produces a paradoxical antibody formation against this, and adverse immunological reactions. We reviewed the immunodeficiency in this paper, highlighting the frequency, pathogenia, clinical diversity and therapy.