A 3-year old boy with Neurofibromatosis-1 presented with persistent respiratory symptoms and X-ray changes. High resolution Computerised Tomography (CT), bronchoscopy and spiral CT showed a mediastinal mass encasing and compressing the left main stem bronchus. Surgical removal and histology of the mass revealed a neurofibroma. Repeat scan six months post-surgery showed some persistence of the mass. Symptomatic, mediastinal neurofibroma in the Paediatric age group is very rare. We could not find any previous report of a neurofibroma encasing the mediastinal structures. This case also demonstrates that persistent respiratory symptom in a patient with Neurofibromatosis-1 warrants a search for intra-thoracic Neurofibroma.