The authors present their US findings in 24 patients with proved complicated midgut malrotation: volvulus in 18 and occlusive Ladd's bands in 6. All the 24 patients have had US examination prior to surgery. Contrast examinations were performed in only 9 patients, always after US and before surgery. The sonographic "whirlpool" pattern of the superior mesenteric vein and mesentery around the superior mesenteric artery was detected in 15 of the 18 patients with midgut volvulus, and was best seen using Doppler color. Embryological signification of midgut malrotation is discussed.