The influence of the viscosity of the reaction medium on the kinetic parameters of the coupled enzyme system of bioluminescence bacteria NAD(P)H:FMN-oxidoreductase-luciferase was investigated. It was shown that in an experimental model of coupled bioluminescent enzyme system with sucrose the reaction rate inhibited to a lesser extent compared with glycerol. The value of the total yield of luminescence and a constant decay of coupled bioluminescent enzyme system do not depend on the viscosity of the reaction media.