A total of 18 anatomically normal human fetal specimens (16 to 26 wk old) were studied. The majority of the deciduous lateral incisors apparently develop in a rotated position during the 2nd and 3rd trimesters; most of them rotated in the lateral or mesiolabial direction. A rotational field affects both jaws simultaneously. There must be subsequent rotation operating in the reverse direction at some point between the 3rd trimester and the time of clinical emergence.