Chronic rhinosinusitis (CRS) is estimated to affect over 35 million people. However, not all patients with the diagnosis respond to standard medical and surgical treatments. Although there are a variety of reasons a patient may be refractory to therapy, one possible etiology is the presence of an underlying immunodeficiency. This review will focus on the description, recognition, and treatment of several antibody deficiencies associated with CRS, including common variable immunodeficiency (CVID), selective IgA deficiency, IgG subclass deficiency, and specific antibody deficiency (SAD). The diagnosis of antibody deficiency in patients with CRS is important because of the large clinical implications it can have on sinus disease management. CVID is treated with immunoglobulin replacement, whereas SAD may be managed symptomatically and sometimes with prophylactic antibiotics and/or immunoglobulin replacement.