Marked differences in the behavior of short (SS) and long-sleep (LS) male C57BL/6 mice were found 21 h after a one-time oral administration of ethanol (0.5, 1.0, and 2.0 g/kg), namely a significant prolongation of the time spent in the light compartment, i.e., the inhibition of dark preference (of the hole reflex) was observed only in SS mice. 15 min after ethanol administration opposite changes took place the time spent in the light compartment was shortened in SS mice and prolonged in LS mice. A smaller dose of ethanol (0.5 g/kg) activated the locomotion in SS mice and inhibited it in LS mice. It seems promising to compare the behavior of SS and LS mice over a period of the ethanol withdrawal.