At adults with a failure an alfa-1-antitrypsin (A1A) the emphysema of lungs, to small nodular cirrhosis often develops. Concentration A1A decreases at homozygote, and at heterozygote that worsens the forecast and raises mortality at this group of patients. Research objective: to study clinical value of depression of level A1A at patients with chronic diseases of a liver. Material and methods. The A1A level was studied in two groups of patients: the 1st group included 22 patients with Wilson's disease (WD) and the 2nd group of 39 patients with a lesion of a liver of various etiology of 32 (84%). By the patient it was carried out the general blood test, biochemical blood test, A1A to bloods, and mutations in AAT gene, a polymorphism on alleles of PiMM, PiMS, PiSS, PiMZ, PiZZ are studied. Results. By results of genetic research in the surveyed group of patients 1 patient with a polymorphism of a gene of A1A as PiMS was found in the others PiMM type became perceptible. Among sick BVK at 6 (26%) patients depression of level A1A 57 (56.7-60) of mg/dl, at 8 became perceptible (36%) patients fluctuated within norm of 173.5 (95-195) mg/dl and at 8 (36%) patients was raised - 278 (222-560) mg/dl, (р<0.001). Depression of level of A1A was bound to depression of fraction of direct copper and augmentation of removal of copper from the patient's organism. In group of patients with chronic diseases of a liver the A1A level fluctuated from 67.5 to 1875 mg/dl. Depression of the A1A level became perceptible at 5 (13%) patients, the normal A1A level became perceptible at 19 (49%) patients, at 15 (38%) rising of the A1A level became perceptible. Negative correlation between the A1A level and biochemical indicators of a cytolytic and cholestatic syndrome was established. A1A vs AST r=–0.4, p=0.01; A1A vs ALT r=–0.32, p=0.047; A1A vs GGTP r=–0.35, p=0.028; A1A vs AP r=–0.38, p=0.017. Depression of level A1A is adverse prognostic criterion at patients with chronic diseases of a liver.