Visual development was assessed in 124 infants (112 preterms and 12 fullterms) who had suffered from perinatal hypoxia and in 55 control preterm infants during the first year of corrected age. Using behavioural techniques, visual functions were tested during follow-up visits in the Sophia Children's Hospital. Corrected ages at testing ranged from 3 months to 1 year. During this period, infants with perinatal hypoxia showed more abnormalities in visual functions than preterm control infants. Gestational age at birth did not influence the outcome of visual development after perinatal hypoxia. Most visual impairments were demonstrated at 3 and 6 months of age. All infants with severe neuro-developmental handicaps showed visual deficits, although neuro-developmental abnormalities and visual deficits could be present as isolated phenomena. Ultrasound abnormalities related well with visual dysfunctions. Prospective studies of infants with visual deficits and a history of perinatal hypoxia are indicated.