In this investigation male rats were kept under controlled environment with LD 12:12 cycle or under constant light condition. Fasted or non‐fasted animals from each group were injected with 25% ethanol (2 g/kg) one hour prior to sacrificing the animals. Fasted or non‐fasted animals kept under LD 12:12 showed a circadian variation in plasma, liver and kidney ethanol levels. Fasting produced a peak shift of ethanol levels in the bloodas well as the tissues studied. There was significant circadian variations in plasma ethanol level of non‐fasted animals kept under constant light. However, fasted animals kept under constant light exhibited “free running”; pattern in relation to ethanol levels. Data from this work suggest that fasting and light conditions can alter the circadian pattern of plasma ethanol levels.