Alpha-1-antitrypsin (Pi) types and subtypes in a Chinese population of 1049 unrelated individuals in Beijing were determined by separator isoelectric focusing. The low activity Pi variant S and the deficient Pi variant Z, common in most Caucasian populations, are absent in the Chinese population. The frequent Pi variant found in the Chinese population is a neutral mutant, Etokyo, which was only found in Japanese before. Thus, it is concluded that, as a predisposition of obstructive or some other lung diseases and liver diseases, the genetic determined deficiency of alpha-1-antitrypsin in Chinese is not so important as in most Caucasian populations.