Superior vena cava (SVC) syndrome is an uncommon complication of malignant disease caused by the obstruction of venous blood flow in the SVC. When present, a diagnosis of lung cancer or lymphoma will be made in approximately 95% of cases. Although other malignant diseases are occasionally associated with SVC, its occurrence in patients with prostate cancer is rare. We present a case of a patient presenting with SVC obstruction who was subsequently diagnosed with prostate adenocarcinoma. The patient has been successfully treated with GnRH agonist. This case reflects the importance of a full clinical assessment and pathological confirmation of suspected tumour prior to treatment.