Retrosternal goitre is usually referred to as enlarged thyroid gland with greater than 50% of its mass below the thoracic inlet. It has a clinical importance because its compressive symptoms may cause diagnostic problems and the selection of surgical approach is sometimes difficult. This report presents a case of shortness of breath in a young female who was treated as a case of long term asthma and was then discovered to have a huge retrosternal goitre extending down to the aortopulmonary window. The mass was resected through median sternotomy and the patient was discharged in a good condition and without further need for asthma treatment.