This study assessed the frequency of primary immunodeficiency diseases in 59 adult patients with non-cystic fibrosis bronchiectasis. The mean age of patients was 50.4 years, and mean age at bronchiectasis diagnosis was 38.9 years. Primary immunodeficiencies were diagnosed in 6 patients (10.2%): 2 with previously diagnosed conditions and 4 with new diagnoses, including 3 with IgA deficiency. An additional 5 patients (8.5%) had borderline levels of anti-pneumococcal antibodies and require further investigation. Mild immunological defects were most common, but some patients had more severe deficiencies requiring specific treatment.