Acute respiratory infections are the most common diseases in all age groups in the world. Lower respiratory infections are the main reason of death, hospitalization and antibiotic use in immunocomprised patients and/or patients with respiratory system chronic diseases. The leading role plays viruses: rhinoviruses, influenza and parainfluenza viruses, respiratory syncytial viruses (RSV), adnenoviruses and coronaviruses. The "youngest" pathogen in this group are human metapneumowiruses (hMPV), identified in 2001. They are the reason of infections in infants, older adults and immunocomprised patients. Manifestation of the infection can have a form from a self-limiting upper respiratory tract inflammation, through bronchitis (in adults), bronchiolitis (in infants) and pneumonitis (in infants and adults), and extremely of severe acute respiratory failure with a need of mechanical ventilation. The authores describe microbiological, epidemiological and clinical features on infection with hMPVs.