Summary Two cases of equine encephalomyelitis (western strain) in infants are reported. Specific antiviral substance was demonstrated in the blood in both. Both cases presented permanent nervous sequelae as a result of the infection. These consisted of cerebral atrophy with overlapping of the cranial bones, mental deterioration, and apparent blindness and deafness in the first patient; mental deterioration with partial hemiplegia and speech defect in the second. Reports of other cases in the literature are reviewed and tabulated.