The influence of temperature stress and starvation for amino acids, glucose and phosphates, on the heat resistance of mycelium and endo- and aminopeptidase activity of Streptomyces hygroscopicus 155, was studied. The strongest growth inhibition was determined at temperature elevation from 30° to 39°C and at starvation for amino acids. Also these stress treatments mostly induce the heat resistance of the mycelium. A correlation between the intracellular endo- and aminopeptidase activity and decrease in biomass yield was registered. The process of catabolization of proteins, during the adaptation to stress treatments, depends on energy and is stimulated by the presence of Mg2+ ions.