The present invention relates to a process for the production of human urokinase. More precisely, the present invention relates to a process for the mass production of human urokinase, comprising in vivo multiplication of human cells capable of producing human urokinase, using the nutrient body fluid of a non-human warm-blooded animal, and exposure of the multiplied human cells to an urokinase inducer. The human urokinase present production according to the invention is much higher than that attained by conventional methods; thus, human urokinase can be used in sufficient amount in the prevention and treatment of human diseases.