Objective: In recent years, culture-independent methods led to provide a strong background to further microbiota studies, especially in lower respiratory tract investigation. Scientific research has focused more on studying and characterizing relationships between lung microbiota and various diseases, such as lung cancer, chronic obstructive pulmonary disease (COPD), asthma, sarcoidosis, acute respiratory infection, etc.

Materials and Methods: The electronic search was performed on the PubMed database using the combination of the text words “respiratory microbiota” and “lung microbiome”. Only research studies in humans published between March 2022 and March 2023 were eligible for inclusion.

Results: The scientific search retrieved 124 results, from which 106 articles were excluded if they duplicate or did not fit the inclusion criteria. A total of 18 studies were included for review.

Conclusions: These studies have shown that changes in lower respiratory microbiota composition are a variable characteristic of all the aforementioned conditions; the relationship between circulating biomarkers, clinical data, and dysbiosis also was found in several studies. However, some studies had limitations, and future investigations are needed to better understand lung microbiota involvement in the pathogenesis of respiratory diseases.