The perpendicular scale of electron phase-space holes is investigated using electric field data from the Polar Plasma Wave Instrument. We show that the electron phase-space holes are roughly spherical for &OHgr;e/&ohgr;p>1, and become more oblate (with the perpendicular scale larger than the parallel scale) with decreasing &OHgr;e/&ohgr;p. A scaling argument based upon electron gyrokinetic theory is proposed as a possible explanation for the observed scaling. The data indicate that the ratio of the parallel dimension (L∥) to the perpendicular dimension (L⊥) is such that L∥/L⊥≃(1+&rgr;e2/&lgr;D2)-1/2. Our results provide a connection between the Geotail measurements in the deep magnetotail, where &OHgr;e/&ohgr;p≪1, and the FAST measurements in the low altitude auroral zone, where &OHgr;e/&ohgr;p≫1. ¿ 2000 American Geophysical Union