Spraints of otter Lutra lutra (Linnaeus, 1758), collected from lake Kerkini and stream Milli during autumn and winter, were examined for prey remains. The overall feeding habits were not similar in the two areas. In Kerkini lake, fish was the most important food item (98% by frequency of occurrence). The most important food species were Lcpomis gibbosus, Carassius auratus gibelio and Rutilus rutilus. In Milli stream the most important food items were crayfish (78.4%) and fish (67.6%). Mammals proved to be an important food category for otters. They occurred in 20% of the spraints in the lake Kerkini and 29,7% of the spraints in the stream Milli.