Glanzmann thrombasthenia is a rare hereditary qualitative platelet disorder characterized Dy a lifelong bleeding tendency due to quantitative and qualitative abnormalities of the platelet integrin αIIbβ3. Common clinical manifestations include purpuric type skin bleeding, prolonged bleeding from minor cuts, epistaxis, gingival bleeding and menorrhagia. Less frequently, gastrointestinal system bleeding may occur. Haemarthrosis, haematuria, intracranial and visceral haemorrhage are very rare symptoms. This study reports a 3-y-old girl with Glanzmann thrombasthenia who presented with life-threatening haemothorax. There was no history of recent trauma or drug usage and no vascular or parenchymal abnormalities to explain the development of haemothorax. Conclusion: To the authors' knowledge this is the first case of Glanzmann thrombasthenia complicated by spontaneous haemothorax.