60 consecutive patients with bronchiectasis were screened for alpha1-antitrypsin deficiency. Six cases (10%) with genotype PiMZ (alpha1-antitrypsin less than 66% of normal) were found. This frequency (10%) was statistically significantly (p less than 0.005) higher than the frequency of PiMZ (2.7%) in the control group. In two patients the bronchiectasis was cystic. It is suggested that the deficiency states of alpha1-antitrypsin promoting the proteolysis can participate in the genesis of bronchiectasis.