Chemoluminescence arised after incubation of diluted blood plasma with hydrogen peroxide. A typical pattern of the luminescence development, similar to that obtained on addition of H2O2 to other biological objects, was observed: quick increase and gradual decrease to a steady-state chemoluminescence level. The increase in chemoluminescence, which was noted in some experiments, might be due to elevation in content of both initiators of peroxidation and activators of the chemoluminescence in blood plasma. Kinetics of the chemoluminescence did not correlate with concentration of oxygen in media.