Kawasaki disease (KD) is a self-limited vasculitis with significant morbidity and even mortality if not treated early. The diagnosis and timely treatment in children younger than 3 months is challenging, most of them have an incomplete or atypical presentation. Coronary artery abnormalities are frequent in this type of patients. We present a 6-week-old female infant with Kawasaki disease who developed a giant coronary aneurysm. The timely diagnosis and promptly treatment as well as the echocardiographic and multimodality follow-up allowed us to improve our clinical approach and management.