Chlamydial infection in human urogenital tract induces inflammation and causes tissue damage and scarring. It is thought that cytokine production by the Chlamydia-infected cells plays a key role in chlamydial disease processes. Although many cytokines have been detected during chlamydial infection, little is known about the molecular mechanisms on how Chlamydia triggers and sustains the inflammatory cytokine cascades. In the current study, chlamydial infection of the human cervical epithelial cell line HeLa cells can induce the production of IL-8, IL-1α, IL-1β and IL-6. Using inhibitors for probing intracellular kinase signaling pathways required for the Chlamydia-induced cytokines, it was found that the Chlamydia-activated MAPK / P38 pathway is required for the chlamydial induction of IL-1α and IL-6 while both the Chlamydia-activated MAPK/ERK and MAPK/P38 pathways contribute to the production of IL-8.