Chlamydia psittaci is a gram-negative, obligate, intracellular bacterium, which mainly infectsbirds and mammals. Not much is known about innate immunity initiated by C. psittaci. Thefocus of the present study is on chicken macrophage activation and expression of cytokine,chemokine, caspase-1, iNOS and TLR genes during the early phase and mid-cycle period ofthe developmental cycle of the highly virulent C. psittaci strain 92/1293. C. psittaci significantlyaugmented the transcript levels for all genes investigated, especially during the mid-cycle period.These results demonstrate a robust innate immune response of chicken macrophages initiated bya C. psittaci infection.