Patients with primary antibody deficiencies have an increased frequency of sinonasal and pulmonary infections. Immunoglobulin (Ig) replacement is a standard therapy for common variable immunodeficiency (CVID) and other antibody deficiency diseases. Although there is convincing evidence that Ig replacement reduces pulmonary infections, there is little evidence that it reduces sinus infections or abates chronic rhinosinusitis (CRS). This study aims to identify the impact of Ig replacement on CRS in antibody deficiencies.