BACKGROUND Ileal atresia is a congenital abnormality where there is significant stenosis or complete absence of a portion of the ileum. The overall diagnostic accuracy of prenatal ultrasound in detecting jejunal and ileal atresia is low. We report a case of ileal atresia diagnosed prenatally by ultrasound examination with the “keyboard sign” and “coffee bean sign”. CASE SUMMARY We report a case of ileal atresia diagnosed in utero at 31 weeks' of gestation. Prenatal ultrasound examination revealed two rows of intestines arranged in an ‘S’ shape in the middle abdomen. The inner diameters were 1.7 cm and 1.6 cm, respectively. A typical “keyboard sign” was observed. The intestine canal behind the “keyboard sign” showed an irregular strong echo. There was no normal intestinal wall structure, showing a typical “coffee bean sign”. Termination of the pregnancy and autopsy findings confirmed the diagnosis. CONCLUSION The prenatal diagnosis of ileal atresia is difficult. The sonographic features of the “keyboard sign” and “coffee bean sign” are helpful in diagnosing the location of congenital jejunal and ileal atresia.