Mycoplasma pneumoniae pneumonia occurs periodically in an endemic-epidemic pattern. The incidence of this disease has fallen drastically as a result of the health measures imposed for the COVID-19 pandemic. In Switzerland, as elsewhere in the world, a new epidemic has been affecting pediatrics and adult populations since September 2023. Transmitted by aerosols and requiring close contact, this bacterium causes respiratory infections of varying severity, as well as a variety of extra-pulmonary manifestations. Microbiological diagnosis is based on PCR of respiratory samples. Despite a very high rate of macrolide resistance in Asia, the resistance rate remains low in Europe.