High affinity to the epithelial lining of the airways makes Chlamydophila pneumoniae a common etiological agent of respiratory tract infections (RTI). It causes among others: pharyngitis, tracheitis, sinusitis, otitis media, bronchitis and bronchiolitis, and pneumonia. It is estimated that Chlamydophila pneumoniae infection is responsible for about 20% of lower respiratory tract infections. Chlamydophila pneumoniae infection may play an important role in the pathogenesis and course of bronchial asthma. The recent results indicate that Chlamydophila pneumoniae infection may be a factor responsible for 4-16% of COPD (Chronic obstructive pulmonary disease) exacerbations. A relationship of chlamydial infection with atherosclerosis raises huge interest. A connection of Chlamydophila pneumoniae infection with other non-communicable diseases such as lung cancer, arthritis, Alzheimer's disease, multiple sclerosis, sarcoidosis and erythema nodosum is also recognized, although the role of these bacteria has not been fully understood in any of the listed diseases (Adv Clin Exp Med 2014, 23, 1, 123-126).