BACKGROUND: Hamartoma of the thoracic wall is a rare benign tumor that occurs in infancy and can be mistaken for a malignancy due to its clinical and imaging features. Hamartomas are extrapleural soft tissue lesions that cause rib expansion and destruction and appear on imaging as cystic areas with fluid levels and calcification. They can cause scoliosis, pressure on the neighboring lung parenchyma and mediastinal displacement. While conservative treatment is recommended in asymptomatic cases, growing lesions require surgical excision. CASE REPORT: In this report, we present the imaging findings in a 3-month-old infant that presented with a firm swelling in the chest wall and was histopathologically confirmed to have a bilateral multifocal hamartoma. CONCLUSIONS: Radiological imaging methods are important for accurate diagnosis of this very rare condition that can be confused with a malignancy.