This study was undertaken to define the role of ultrasound (US) and magnetic resonance (MR) imaging in the diagnosis and preoperative staging of cervico-thoracic lymphangiomas in children. In a retrospective study, 11 patients with surgically and pathologically proved lymphangiomas had MR imaging and 6 of them underwent simultaneous US. US showed superficial hypoechogenic multioccular cystic masses with septa of variable thickness, but failed to demonstrate retropharyngeal, axillary or mediastinal extensions in all patients. All lesions were identified on both MR T1-weighted images (T1WI) and T2-weighted images (T2WI). T2WI provided the best tissue contrast between the lymphangiomas and surrounding tissues. T1WI after i.v. injection of gadolinium DOTA (Gd DOTA) in two patients provided additional information regarding the extent of the lesion. The authors concluded that although lymphangiomas have a distinctive sonographic appearance, MR imaging allowed a better tissue characterisation and tumour extent. T2WI and T1WI after i.v. injection of Gd DOTA are especially helpful for the diagnosis and preoperative staging of cervico-thoracic lymphangiomas in children.