Pleural effusion is a common phenomenon occurring due to various causes. Pulmonary embolism is a less common cause of pleural effusion. In our case patient presented with minimal pleural effusion but thorough investigation revealed the underlying homocystenaemia.Thus, we concluded that pleural effusion represents the tip of iceberg of more serious underlying disease. 

Keywords: Pulmonary embolism; Pleural effusion; Homocystenemia.