Endocarp morphology of 4 species of Iranian Celtis was examined using light and scanning electron microscopes. Macro- and micro-morphological characters were included endocarp shape, color, size, surrounding rim, ornamentation and SEM structure of the outer layer of the endocarp. Endocarp morphology of the examined specimens exhibit variation in all characters. Endocarp shape varies from globular to ovoid-acuminate. Endocarp size ranges between (5.5×5×4.5 mm) and (8×6×5.5 mm). Endocarp color varies from milky to russet. The results of SEM investigation of the outer endocarp show holes with 5-25 µ diameters. Iranian Celtis Can be distinguished by the means of endocarp morphology but other characters are also needed.