To evaluate the prefrontal space (PFS) ratio of fetuses of African descent without Down syndrome and compare it to the PFS ratio previously established in a homogeneous Caucasian population to determine whether there is a difference in the ratio in these two groups. The PFS ratio was calculated retrospectively from stored 2D images of 100 African, African-American and African-Caribbean fetuses in the second and third trimester performed at the authors’ center. Other data including the maternal age, gestational age, and ethnicity were collected. An unpaired T test was used to compare the previously published Caucasian mean, 0.97 (SD 0.29) with the mean established for the black population 1.37 (SD 0.44). The difference between these two PFS ratios was found to be significant (p < 0.0001). This pilot study suggests a significant difference in the PFS in the non-Caucasian population. In order to use the PFS as a sonographic screening tool for Down syndrome, it will be important to determine normal values in different ethnic populations.