Hemothorax is a rare but potentially fatal postthoracentesis complication. Early clinical signs may be nonspecific resulting in diagnostic delay. A high index of suspicion is vital for early diagnosis and intervention to avoid further bleeding. Following procedure, early bedside ultrasound findings can be vital for early detection. We report a case of massive hemothorax in a 63-year-old male following therapeutic thoracentesis. Diagnosis was made following highly suggestive sonographic findings prompting thoracotomy and lacerated intercostal artery cauterization.