Social influences on drinking ethanol solution were studied in two cats ("drinkers") who voluntarily drank small amounts of 10% ethanol solution in milk and three other cats ("nondrinkers") who served as companions to the drinkers. A 15-minute session was conducted daily in a compartment divided into two even parts with a transparent Plexiglass partition. The cats were introduced to the compartment either singly or in pairs. Each pair consisted either of two drinkers or one drinker and one nondrinker. Each cat of the pair was placed in one part of the compartment; the cats could see each other, but they could not make physical contact. Each drinker was offered 10% ethanol solution in milk, while each nondrinker was given plain milk, and the amount of consumption was measured. A series of five to ten sessions with a drinker was followed by a series of sessions with a nondrinker or with no companion. There were a total of 13 series of sessions for each drinker. A statistical analysis of the data showed that, in most series, the mean amount of consumption of ethanol solution was significantly higher in the presence of a companion (either drinker or nondrinker) than in its absence.