Galactocele is a rare breast condition in infants. Here, we report a 16-month-old boy who developed progressive left breast enlargement. Ultrasonography and magnetic resonance imaging revealed a 4 cm cystic lesion at left breast. Hormonal assay showed transient hyperprolactinaemia with no known cause identified. Subsequently, galactocele was confirmed on histopathological examination after complete surgical excision. No recurrence was observed on regular follow-up.