Bone marrow transplantation has become widely used in the treatment of aplastic anemia and leukemia. Cyclosporine is used as prophylaxis against graft-versus-host disease. The authors report on eight cases of optic disc edema in patients taking cyclosporine after allogenic bone marrow transplant. Thorough evaluation revealed a possible alternate cause in two cases. In all cases, the optic disc edema resolved after discontinuing or decreasing the cyclosporine. Although cyclosporine has not previously been associated with optic disc edema, it has been implicated as the cause of a variety of neurologic side effects. Bone marrow transplant patients taking cyclosporine should be followed for the development of optic disc edema.