This histological study reports the pathological findings in mice deficient in essential fatty acids (EFAD). As shown by others, hyperplasia and hyperkeratosis were observed in skin. In addition, we reported hyperkeratosis of the esophagus and forestomach, severe degrees of atrophy of the seminal epithelium of testes, and diminution of the luminal content of epididymis, and the formation of clusters of lipid-laden macrophages in lungs. Hyperemia was also a systemic change in many organs. These alterations have not been reported in EFAD mice previously.