The state of binding centers in albumin molecule in patients with anxious depression was studied by the method of quenching of fluorescence of molecular probe (dimethyl-aminonaphthaleic acid carboxyphenylimide) with nitrate ions. Serum samples from 24 donors without somatic and mental diseases and 26 patients were analyzed. In the absence of the quenching agent, specific fluorescence of the probe (standardized by albumin concentration) was lower in patients with depression. The fluorescence quenching constant and the percentage of fluorescence available for quenching were also lower in serum samples from patients. These data indicate that the parameters of binding centers in albumin molecule in patients with anxious depression are significantly modified in comparison with normal subjects. The detected changes can play a role in the pathogenesis of depressive disorders.