**Abstract**

Asthma is the most common chronic disease in childhood and it is a major global health problem. Asthma is characterized by chronic airway inflammation and the pathogenetic mechanisms leading to asthma are likely to be diverse, and influenced by multiple genetic polymorphisms as well as environmental factors, including respiratory tract infections. *Chlamydia pneumoniae* is a human pathogen belonging to the Chlamydiae family. Since its recognition in 1989, *C. pneumoniae* has been extensively studied for its role as a widespread respiratory pathogen and its potential consequences in both children and adults. Its ability to evade the human immune system, biphasic development cycle, and capacity to spread throughout the host has made it a suspect in many chronic inflammatory diseases, including asthma. Chlamydia pneumonia is of particular interest among the various infections associated with newonset asthma, asthma severity, and treatment resistance.

**Keywords:** *Chlamydia pneumoniae*, asthma, childhood asthma, infection-related asthma, severe asthma
