Twenty patients with chronic refractory sinusitis or rhinitis were identified to have immune defects on the basis of total immunoglobulin level, immunoglobulin G subclass, and vaccine response. Eight patients were immunoglobulin A deficient, five had low immunoglobulin levels with vaccine hyporesponse, and four had low immunoglobulin levels with normal vaccine responses. Three subjects showed isolated immunoglobulin G1 deficiency. Demographic variables such as age, sex, infection pattern, and any other related disorders were studied retrospectively, which may have contributed to the diagnosis. An immunologic screen was essential for the diagnosis of immunodeficiency in these patients. Treatment options included prophylactic antibiotics, management of associated allergies, functional endoscopic sinus surgery, and replacement therapy with immunoglobulin in selected patients.