Abstract: The invention relates to new expression vectors. More particularly, the invention relates to expression vectors carrying a new type of promoters for the expression of the foreign gene, which was constructed from promoter P.sub.2 of E. coli ribosomal RNA operon and some regulatory sequences of E. coli las operon. The invention further relates to a method for the construction of the above vectors. The method is characterized by deleting most part of the structurgenes of E. coli ribosomal RNA operon (rrn operon) built in a suitable vector, joining together the part of operon rrn comprising promoter P.sub.2 with the beginning part of the lac operon outside the regions -35 and -10, downstream of them so as to create a new NsiI cleavage site at the joining point of the sequences originating from rrn and lac operons, deleting the inner TGCA sequence-element of the newly created NsiI cleavage site and building the structurgene to be expressed between these newly created regulatory sequences.