An asymmetry in D-2 receptor densities (Bmax) measured by [3H]N-methyl spiperone binding was found in striata from female Sprague-Dawley rats. The D-2 Bmax on the right side was on average 40% greater than the D-2 Bmax on the left side. This asymmetry is greater in magnitude and opposite in direction to that reported for males and is independent of directional preference exhibited during nocturnal circling.