Experimental data on the impact of argon-containing hypoxic breathing mixtures on the early embryonic growth of Japanese quail (Coturnix coturnix japonica dom.) are presented. The results showed that after 4-day incubation of eggs in an oxygen-nitrogen breathing mixture (13.8-15.0% O2, 86.2-85.0% N2) only 16.7% embryos reached the stage of 3.5-d development. Introduction in the hypoxic mixture of argon (55% of the total volume) increased the number of embryos on the stage of 3.5-4 day of normal morphological development to 60%. It became evident from the analysis that embryos developed in the O2-Ar-N2 hypoxic mixture had 25% less pathologies as compared with embryos developed in a largely nitrogen-containing gas mixture. Hence, we received the experimental evidence that 55% of argon in a hypoxic breathing mixture with up to 15% of oxygen is favorable to the early embryonic growth of Japanese quail stimulating metabolic processes in germ organism.