Blunt abdominal trauma causing jejunal perforation is rare occurrence and is usually expected after a motor vehicle accident. In this study, we present a case of jejunal perforation caused by impact of a knee to the abdominal area. A 21-year-old man was admitted to the emergency department after blunt trauma caused by a knee kick. He described a sudden pain at the whole abdomen after trauma. On his physical examination, there was tenderness on the left abdomen at palpation. All blood tests, pulse rate, temperature, and blood pressure were within normal range. Free air was detected under the diaphragm on upright plain x-ray. Computed tomography revealed free air and fluid in the abdomen. In the laparotomy, approximately 200 cc of intestinal fluid was found leaking from a jejunum perforation on the antimesenteric aspect, 60 cm from the Treitz ligament. Resection was performed and ends of the intestines sutured primarily. The patient was discharged from the hospital on the 10th postoperative day without any complication. The diagnosis of jejunal perforation after blunt trauma is a dilemma. The mechanism of injury, history, and serial physical examination play an important role in diagnosis. Therefore, there is a suspicious aspect to this kind of case. For optimal management, repeated physical examination and available radiologic techniques are important cornerstones.