We describe an infant with Chikungunya virus (CHIKV) infection who developed Horner syndrome. The infant had diagnostic confirmation of CHIKV infection by IgM-ELISA positive in serum and cerebrospinal fluid, and clinical signs of Horner syndrome. Magnetic resonance angiography showed alterations in the cervical and intra cavernous portions of the internal carotid artery. To the best of our knowledge this is the first report of the association of CHIKV infection with Horner syndrome.