The clinico-pathological aspect of an unusual case of thrombotic microangiopathy (M.A.T.) is reported in acute leukemia one year after bone marrow graft. The patient was first seen complaining of blurred vision in both eyes. Ocular findings included choriocapillaris and retinal vascular occlusions, resulting in bullous retinal detachments, massive retinal exudation and cystoid macular edema. The relationship between M.A.T. and bone marrow grafting is discussed with respect to the immunological disorders or graft-versus-host reaction and the role of irradiation.