Common variable immunodeficiency (CVID) is a common primary immunodeficiency characterized by a failure in B-cell differentiation with defective immunoglobulin production. Affected patients are uniquely susceptible to recurrent infection with encapsulated organisms and have an increased propensity for the development of inflammatory and autoimmune manifestations. The diagnosis of CVID is commonly delayed and the underlying cause of the disorder is not understood. Replacement antibody therapy reduces the risk of serious infections. However, optimal treatment regimens for the uncommon manifestations associated with this disease, such as granulomatous lymphocytic interstitial lung disease, require further research.