Streptokinase gene (Skc) containing the promoter and signal sequence was cloned in B. subtilis using the pUB140 plasmid vector. The streptokinase gene was expressed and streptokinase was secreted into culture broth. The coding sequence of the streptokinase gene was also expressed as fused gene using promoter and signal sequence of α-amylase gene from B. subtilis NA64 strain. In this α-amylase secretion vector system, streptokinase activity in culture broth was two to three-fold higher than that with its own promoter and signal sequence.