Telocytes (TCs) are a new type of interstitial cells, a small cellular body with the presence of 2–5 prolongations named as telopode (Tp)-very thin (less than 0.2 µm) and extremely long (10–1,000 µm), a moniliform aspect, and caveolae, containing a nucleus surrounded by a small amount of cytoplasm. The nucleus occupies about 25% of TC body volume and contains clusters of heterochromatin attached to the nuclear envelope. The perinuclear cytoplasm is rich in mitochondria and contains a small Golgi complex, rough and smooth endoplasmic reticulum and cytoskeletal elements. TCs have several immunophenotypes such as CD34, c-kit, and vimentin. TCs were found in many organs of mammals with potential biological functions, even though the exact function remains unclear. Recently, we identified and isolated TCs from the trachea for the first time and confirmed the existence of TC in lung tissues, which could have the potential significance in the pathogenesis of pulmonary diseases. Future efforts are required to clarify pathophysiological functions of TCs in the disease. J. Cell. Physiol. 227: 2311–2317, 2012. © 2011 Wiley Periodicals, Inc.