Chlamydial infections are prevalent worldwide. Immunological events related to both innate and adaptive immunity during chlamydial infection can aid in recovery from the disease, but they can also cause harmful effects (immunopathology). The host genetic factors (variation in innate immunity and adaptive response-related genes) can predispose individuals to infection and its sequelae as well as determine the effects of intervention. No effective vaccine is available for human use. Modern technologies and data obtained using different 'omics' techniques (genomics, proteomics, transcriptomics and immunomics) might help in designing novel, more efficient vaccines, hopefully also against chlamydial infections.