Mycoplasma pneumoniae pneumonia is one of the most prevalent community-acquired pneumonias in pediatric patients. It commonly presents with mild respiratory symptoms and is well controlled by macrolide antibiotics. Rarely, it can progress to acute respiratory distress syndrome (ARDS) despite appropriate antibiotic therapy, and systemic corticosteroids and quinolone antibiotics are required. We recently treated 2 patients who presented with M. pneumoniae pneumonia with ARDS. Case 1: A 17-year-old girl was admitted with pneumonia that showed no response to antibiotics and progressed to ARDS, which required initiation of mechanical ventilation therapy. The patient was negative for M. pneumoniae IgM; but positive for, M. pneumoniae. After treatment with methylprednisolone and levofloxacin, rapid improvement was observed in both clinical manifestations and chest radiographic findings. Two days after discontinuing a 5-day methylprednisolone treatment regimen, she developed fever, and investigations revealed an elevated C-reactive protein level; this necessitated additional methylprednisolone treatment. Subsequently, she showed complete recovery with no sequelae. Case 2: A 14-year-old girl was admitted with M. pneumoniae pneumonia with ARDS that required mechanical ventilation therapy. She showed a IgM titers against M. pneumoniae of 1:320. After treatment with antibiotics and methylprednisolone, she recovered and was discharged at 48 admission days; however, mild dyspnea persisted. The chest computed tomography showed multiple bronchiectasis areas. After 15 days, because of aggravated dyspnea, she was readmitted and adminis-tered methylprednisolone pulse therapy. Despite 3 courses of methylprednisolone pulse therapy, she still showed mild dyspnea.