We report on two cases of microdeletion of chromosome sub-band 2q37.3 with abnormal situs viscerum. The first patient had dextrocardia, duodenal and jejunal atresia, and an abdominal hernia. The liver was in the left upper quadrant, stomach in the right upper quadrant. In contrast anema the ascending colon was in the left, and descending colon on the right, with an area of atresia in the mid-jejunum. The second patient had malrotation and malposition of large and small bowel, with most of the bowels positioned above the liver and spleen. There was incomplete rotation of the cecum. The right kidney was malrotated and mal-positioned. The finding of 2q37.3 deletion in both patients implies that a locus or loci involved in the development of normal body situs lies within this chromosome region. Molecular cytogenetic evaluation for a possible 2q37.3 deletion should be considered in patients with abnormal situs viscerum.