In histochemical (with the glyoxylic acid) and biochemical (spectrofluorimetric trioxyindolic method) investigations sources and content of catecholamines (dopa, noradrenalin, adrenalin) in the blood vessels, sympathetic chains, adrenals and cardiac ventricles have been studied in autumn-winter and spring-summer frogs at various temperatures. It was found that the catecholamines in the studied tissues are located in the sympathetic neurons, adrenergic terminals and chromaffin cells. The ratio of these structures in different tissues was various. It was found that the catecholamine level in frog blood vessels and various organs undergoes seasonal and temperature variations. The increase of temperature from + 5 to 20 degrees caused a decrease in the catecholamine level in the autumn-winter frogs, but increased the catecholamine concentrations over 60--100% in the spring-summer ones.