Alpha-1-antitrypsin (PI) phenotypes were studied in a sample of more than 5,000 individuals from cities throughout France. Special interest was paid to the PI*Z allele whose average frequency, based on the present work plus results from the literature, was 0.0130. This figure was used to estimate the number of PI Z homozygotes in France. In accordance with previous studies, the frequency of the PI*S allele was found to increase towards the southern parts of France.