We present a patient with serologically confirmed Epstein-Barr virus (EBV) infection who had illusions of size, shape, and colour of objects but none of the typical symptoms and signs peculiar to infectious mononucleosis (IM) except sore throat which developed 2 weeks after the initial visual disturbances. The bizarre feelings about the images of body and objects are called the 'Alice in Wonderland syndrome' due to the similarity with Alice's dreams. The same symptomatology including visual metamorphosia is defined in patients with migraine, epilepsy, intoxication due to hallucinogenic drugs, schizophrenia, hyperpyrexia, and cerebral lesions. Alice in Wonderland syndrome has also been reported in the course of IM.