Crossed cerebellar hypometabolism on 18F-FDG PET has been well described. However, crossed cerebellar hypermetabolism is rare. We described a case of crossed cerebellar hypermetabolism in a middle-aged woman. The patient underwent FDG PET to assess epileptogenic focus during her subclinical seizure episode, which was shown on video electroencephalography. The crossed cerebellar hypermetabolism was no longer visualized when her subclinical seizure was controlled.