Chlamydia infection is a major public health concern worldwide.The best way to control this infection and to prevent its sequelae is to develop an effective vaccine.DNA vaccination approaches have been tested in chlamydial vaccine development with a certain degree of success.Although significant protection was induced by major outer membrane protein (MOMP) gene immunization,sterile protection was not achieved.The use of DNA priming/protein boosting approaches can significantly enhance the protective efficacy of the vaccination.DNA immunization study has identified several sections of MOMP genes which induce protection.Further studies to identify protective antigens,to enhance the expression of chlamydial antigens in vivo,to manipulate immune response by using various adjuvants and to generate immunity to multiple chlamydial species/strains are major challenges in chlamydial DNA vaccination.