Two lines of rats selected for high- and low-avoidance performance consumed a nutritious liquid diet containing 35% ethanol-derived calories through days 5--18 of gestation. Control dams were pair-fed an identical liquid diet except for isocaloric substitution of sucrose for ethanol or ad libitum laboratory chow and water. Subsequently, the offspring of the low-avoider dams fed ethanol were found to be impaired ona two-way shock-avoidance conditioning when compared to the pair-fed and ad libitum controls from the same line. In contrast, the offspring of the high-avoider dams fed ethanol displayed similar levels of avoidance, responding to their controls. These results demonstrate that the effects on avoidance conditioning of in utero ethanol exposure are dependent upon the line of rat studied.