Dengue virus enters into host cells by binding envelope glycoprotein (E) to a receptor and causes human disease. Domain III of dengue virus E glycoprotein (EIII) is immunogenic and capable of inducing neutralizing antibodies. A DNA fragment encoding EIII (amino acids 297-394) was introduced into tobacco plant cells (Nicotiana tabacum L. cv MD609) by Agrobacterium tumefaciens-mediated transformation methods. The integration of EIII gene was observed in the genomic DNA of transgenic plants by PCR DNA amplification methods. The transcripts of EIII gene were detected in the transgenic plant leaf tissues by Northern blot analysis. The EIII protein was detected in transgenic plant leaf extracts by Western blot analysis. Based on the results of the Western blot analysis, the expression level of plant-produced EIII protein was between 0.13 and 0.25% of the total soluble protein in transgenic plant leaf tissues. The production of domain III of dengue virus E glycoprotein (EIII) in transgenic plants demonstrates the feasibility of using plant-based vaccines to prevent infection by the dengue virus.