Bilateral lesions centered in the posterodorsal amygdala of female rats resulted in hyperphagia and excessive weight gain. The brain damage extended posteriorly through the amygdalohippocampal area and into the ventral hippocampus and subiculum. Lesions centered in the ventral hippocampal formation had a less pronounced, although still significant, effect on body weight. Damage to large areas of the amygdala, including the anterior, basolateral, and corticomedial groups of nuclei, was without effect. A serial reconstruction of overlapping areas of destruction for both effective and ineffective lesions is presented.