We constructed plasmids carrying the human fibroblast growth factor-9 N33 (hFGF-9 N33) gene under the control of the T7 promoter in pBR322. These plasmids were introduced into Escherichia coli MM294 lysogenized with bacteriophage lambda with the T7 RNA polymerase gene under the control of the lacUV5 promoter. We compared the expression level of hFGF-9 N33 in the transformed E. coli MM294(DE3)/pETGAF25 and MM294(DE3)/pTG931 which are ampicillin- and tetracycline-resistant strains, respectively. Twice as much hFGF-9 N33 was produced by MM294(DE3)/pTG931 as by MM294(DE3)/pETGAF25, although the growth rates of these strains were similar. The expression plasmid pTG941, a derivative of pTG931, was constructed by reducing the size of the long non-coding region between the stop codon of the hFGF-9 N33 gene and the T7 terminator. The amount of hFGF-9 N33 expressed in MM294(DE3)/pTG941 was twice that expressed in MM294(DE3)/pTG931, although the growth rates of these strains were similar. The expression level reached a maximum when 10 mg/l of isopropyl beta-D-thiogalactopyranoside, an inducer, was added to the culture at 250 Klett units of growth. Feeding glucose to the culture increased the final growth level and caused a 40% increase in the amount of hFGF-9 N33 produced. Over 0.5 g/l of hFGF-9 N33 was produced in a large-scale culture by improving the expression plasmids and optimizing the culture conditions.