OBJECTIVE: Children born prematurely have a higher incidence of attention deficit disorder with or without hyperactivity. We have used visual event related potentials to study possible brain dysfunctions that could explain this higher incidence. METHODS: Very low birth weight (VLBW) children with and without AD/HD and term born children with and without AD/HD, were matched for IQ, age and socio-economic status (n=41, mean age 104 months). A visual oddball paradigm, consisting of target and non-target stimuli, was used with analysis of response times, error scores, N200, P300 and a P500 component. RESULTS: AD/HD children responded slower (F (1,38)=11.20, p<0.002); more varied (F (1,38)=21.77, p<0.000) and made more commission and omission errors (Kruskal-Wallis p<0.000). Non-target N200 was increased in amplitude (F (1.39)=4.01, p=0.05) with a wide anterior topography in children with AD/HD. The late positivity (P500) was decreased over central leads in children with AD/HD during the non-target stimuli (F (3,75)=3.00, p<0.036). No differences could be found in latency, amplitude or topography between VLBW children with AD/HD and term born children with AD/HD. CONCLUSIONS: Prematurity does not induce specific attentional brain dysfunction or maturation delays in stimulus processing during cognitive tasks. Other factors should be investigated to explain the higher incidence of AD/HD in VLBW children.