<p>Primary sternal osteomyelitis (PSO) is a rare entity in the pediatric population that should be considered in patients with localized pain, erythema, and swelling at the sternal region. Magnetic resonance imaging (MRI) and samples from fine needle aspiration can help in its diagnosis. Management of these patients remains controversial. We present two cases of primary sternal osteomyelitis in the pediatric population. Their main characteristics, as well as the most relevant diagnostic and therapeutic considerations, are described, and they are compared with the available literature. Two patients (a 10-month-old boy and a 17-month-old girl) presented at the Emergency Department with a sternal mass with no fever, the first one with inflammatory signs and the second one without them. Primary sternal osteomyelitis was suspected and magnetic resonance imaging confirmed it in both cases. Both patients were successfully managed with intravenous antibiotics, with no need for surgical drainage. Primary sternal osteomyelitis is a rare entity in pediatrics that should be considered in the presence of inflammatory signs at sternum. Magnetic resonance imaging is highly useful in its diagnosis. In the absence of complications, appropriate and early antibiotic coverage is effective without surgery.</p>