A four-day-old boy presented with persistent bilious vomiting, bloody stained stool, and mild abdominal distension. Transabdominal ultrasound demonstrated a round soft-tissue mass-like structure in the right upper quadrant. With color Doppler ultrasound, the whirlpool sign was observed. Abdominal radiograph showed nonspecific findings. Upper gastrointestinal series revealed upper gastrointestinal tract obstruction at the level of distal duodenum. The diagnosis of intestinal malrotation with midgut volvulus was established and the treated surgically. Intestinal malrotation is congenital abnormal positioning of the bowel loops within the peritoneal cavity resulting in abnormal shortening of mesenteric root that is predisposed to midgut volvulus. Neonates and infants with persistent bilious vomiting should undergo diagnostic workup and preferably ultrasound as the first step. With classic sonographic appearance of whirlpool sign, even further imaging investigations is often not needed, and the surgeon should be alerted to plan surgery.