 Mycoplasma pneumonii is a small bacterium that causes respiratory illnesses in humans. It can lead to both upper and lower respiratory tract infections, resulting in a wide range of symptoms. Symptoms include fever, coughing, sore throat, headache, muscle aches, and fatigue. Cycles of epidemic outbreaks occur every three to seven years in some countries, such as South Korea. Early diagnosis of mycoplasma pneumonii is difficult due to the lack of antibody production, and inconsistent PCR results in the early stages of the infection. Short-term paired IgM serology tests are recommended for an accurate diagnosis. Macrolide antibiotics are typically prescribed for children with mycoplasma pneumonii infections, but resistance to these drugs has been reported in many parts of the world. Immunomodulation treatments, such as corticosteroids or intravenous immunoglobulin, may be beneficial for patients with severe infections. This article was authored by Yu-Sik Yoon and Kang-Yul Lee. We are article.tv, links in the description below.