To examine the interactive effects of ethanol (EtOH) and ambient temperature, 10-, 16-, and 20-day-old rat pups ingested pairings of sucrose solution and various doses of ethanol (intubated intragastrically) and were then exposed to relatively low or relatively high ambient temperatures. Ten- and 20-day-old pups required a higher EtOH dose than did 16-day old pups for conditioning of a sucrose aversion and for hypothermia. These age-related differences might be due to ontogenetic changes in the production and accumulation of acetaldehyde, a metabolite of EtOH. For all ages, EtOH-induced hypothermia was necessary for conditioning of the taste aversion, which is in accord with results of previous tests with adult rats (Cunningham, Hawks, & Niehus, 1988).