The present study was conducted to evaluate the effect of low doses of ethanol on motor activity in selectively bred Sardinian alcohol-preferring (sP) and Sardinian alcohol-nonpreferring (sNP) rats. Ethanol was acutely administered at the doses of 0, 0.25, and 0.5 g/kg (i.p.) immediately before rat exposure to an open-field arena for 15 min. The number of square crossings, used as index of motor activity, was significantly lower in saline-treated sP than in saline-treated sNP rats, suggestive of a genetically determined higher emotional state in sP than in sNP rats. Ethanol administration resulted in a dose-dependent, significant increase in the number of square crossings in sP rats, whereas it was completely ineffective in sNP rats. These results suggest to us that a positive relationship exists between ethanol preference and ethanol-induced motor stimulation in sP/sNP rat lines.