Congenital hyperinsulinism (CHI) during infancy is characterized by inappropriate insulin secretion resulting in persistent hypoglycemia. This can lead to irreversible severe neurological damage in the infant. There are two main histologic subtypes: diffuse and focal, both of which may require different surgical strategies. It is very important to differentiate focal leisons from diffuse leisons. However, the differentiation of diffuse leisons from focal leisons is challenging. Affected pancreatic areas utilize dihydroxyphenylalanine (DOPA) at a higher rate than normal pancreatic tissues; thus, labeling of L-DOPA with fluorine-18 (18F-DOPA) allows functional mapping of hyperinsulinism using positron emission tomography/computed tomography (PET/CT). In this article, we reviewed the 18F-DOPA PET/CT application in CHI. The aim of this review is to enhance the recognition of 18F-DOPA PET/CT application in the diagnosis of CHI.