Tacrolimus is a macrolide immunosuppressant that is widely used in transplant surgery. Both mild and major neurologic side effects have been reported in patients receiving tacrolimus. Reversible posterior leukoencephalopathy syndrome is one of the major tacrolimus induced neurologic side effects. We report a case of a tacrolimus induced isolated lesion of the cerebellum with no supratentorial involvement, presenting as a subacute cerebellar ataxia, which was partially reversible upon discontinuing the tacrolimus.