Abstract Background: The ability of three dimensional ultrasound to acquire and save volume datasets, reconstruct any plane in the volume and allow off-line re-examination and manipulation of these datasets, makes this technology superior to two dimensional ultrasound in many areas. Aim of Study: This study was conducted to determine if there is any added value of 3D US examination in diagnosis of fetal malformations during mid-trimester anomaly scan. Subject and Methods: Pregnant women referred for mid-trimester anomaly scan were prospectively evaluated by 2D US. Fetuses suspected to have malformation by 2D US or with increased risk of a recurrence or strong family history of a congenital abnormality, were evaluated by 3D US. Women confirmed to have fetal malformations postnatally were included. Results: Sixty malformations were confirmed postnatally. 2D US established the diagnosis of fifty seven (95%) malfor-mations and two malformations were detected exclusively by 3D US, and the difference was highly significant [McNemar chi-squared statistic=18, p=<0.0001]. Fifty nine malformations were diagnosed by both 2D and 3D US. Conclusions: 3D US significantly improved the number of detected fetal malformations, than that detected by 2D US. 3D imaging is superior in specific diagnostic problems. Rather than representing an alternative, 3D US is complementary to the conventional 2D US in the field of prenatal diagnosis.