The comprise a group of highly adapted bacterial pathogens sharing a unique intracellular lifestyle. Three species are pathogenic to humans: , and . is the leading bacterial cause of sexually-transmitted infections and infectious blindness worldwide. is a major cause of community-acquired atypical pneumonia. primarily affects psittacine birds and can be transmitted to humans causing psittacosis, a potentially fatal form of pneumonia. As opposed to other bacterial pathogens, the spread of clinically relevant antimicrobial resistance genes does not seem to be a major problem for the treatment of infections. However, when exposed to stressing conditions, like those arising from exposure to antimicrobial stimuli, these bacteria undergo a temporary interruption in their replication cycle and enter a viable but non-cultivable state known as persistence. When the stressing conditions are removed, resumes replication and generation of infectious particles. This review gives an overview of the different survival strategies used by to evade the deleterious effects of penicillin and IFNγ, with a focus on the different models used to study persistence, their contribution to elucidating the molecular basis of this complex phenomenon and their potential implications for studies in animal models of infection.