PROJECT SUMMARY Community-acquired pneumonia (CAP) is the fifth most prevalent but second most costly reason for hospitalization in children. Mycoplasma pneumoniae (Mp) is the most frequently detected pathogen cause bacterial CAP. Although macrolides are recommended for the treatment of Mp CAP there is a lack of clear evidence to support macrolide treatment for Mp has which has likely led to the overuse of macrolides. This R34 application, “Randomized Controlled Trial of Macrolide Therapy for Mp”, will aide in the development of the full protocol and relevant documents for the future trial. In the future trial, we will randomize children who are hospitalized with Mp CAP to receive beta-lactam and azithromycin or beta-lactam and placebo. This trial will provide the necessary evidence for targeted therapy in children hospitalized with Mp CAP, leading to the use of necessary therapy while preventing over-treatment and decreasing complications for children with this prevalent disease.