Pheochromocytomas and paragangliomas are rare neuroendocrine tumours that are an important cause of secondary hypertension. Pheochromocytomas and paragangliomas manifest with a varied clinical picture, including life-threatening hypertensive crises. Persistent, sustained hypertension, the incidence of which far exceeds paroxysmal hypertension, is the predominant clinical manifestation. In the paediatric population, 70–80% of tumours have a genetic background. Hereditary pheochromocytomas and paragangliomas are manifested by early tumour development, bilaterality, multifocality, mainly extra-adrenal localization, and an increased risk of recurrence. Measurement of free metanephrines (MNs) in plasma is considered the gold diagnostic standard due to its high sensitivity and reliable reference values in children. Nuclear medicine plays a key role in the diagnosis of pheochromocytomas and paragangliomas, with high sensitivity and specificity. They are used to assess regional extent, multifocality, and the presence of metastases. Surgical resection preceded by appropriate preoperative preparation is the primary therapeutic approach. Genetic testing and implementation of genetic counselling are recommended in all paediatric patients with confirmed pheochromocytomas and paragangliomas. Scientific evidence and clinical studies on pheochromocytomas and paragangliomas in the paediatric population are limited. The diagnostic and therapeutic process is challenging, often requiring a multidisciplinary approach. The purpose of this paper was to present the clinical picture, genetic background, diagnosis, and treatment of pheochromocytomas and paragangliomas in children and adolescents.