The developmental outcome at 5 years of age was studied in 93 preterm infants who had been prospectively examined for peri-ventricular leucomalacia (PVL). Standardised neurological examination and developmental assessment, including tests of cognitive function, were carried out. Major sequelae (n = 10) could be ascribed in most cases to the presence of large PVL lesions. Children with normal scans (n = 51), with isolated haemorrhage (n = 15) and with post-haemorrhagic ventricular dilatation (n = 3) had a favourable prognosis. Patients with small focal PVL changes (n = 16) had lower cognitive abilities on the McCarthy scale and presented more abnormal neuromotor signs and more attention deficits when compared to children with normal scans and isolated haemorrhage. Small focal PVL changes seem therefore to interfere with development at 5 years of age and might represent a morphological marker of a more diffuse brain injury. This study demonstrated also the effect of socioeconomic status on outcome at the age of 5 years.