Ultrasonographic findings in 11 cases of endophthalmitis are presented. Anterior vitreous echoes and thickening of the retinochoroidal layer were constant findings. Posterior vitreous echoes were seen in nine of the cases, posterior vitreous detachment in seven, and vitreous membrane formation in six. Although vitreous echoes and thickening of the retinochoroidal layer are seen--singly or together--in various conditions, when these findings are present in a patient with signs and symptoms suggestive of infection, the suspicion of endophthalmitis is strong.