The study comprised 324 children with a birthweight less than or equal to 2000 g born in 1971-1974 at the Institute of Midwifery, Helsinki. The low birthweight (LBW) infants totalled 1.46% of the live-born during that time. At the age of 5 years 197 children were investigated; 15 had severe handicaps while 182 were without any immediate noticeable defects. The rest were not investigated for the following reasons: 86 had died, seven were severely handicapped and 34 could not be traced or the parents did not want to participate in the examination. The 197 children were given a neurodevelopmental screening examination, psychological and articulatory tests. A score of greater than or equal to 23 in the neurodevelopmental screening examination was noted in 8% of the controls, in 87% of the severely handicapped and in 34% of children without severe handicaps. All psychological test results differed significantly from those of the controls. The articulatory tests showed that the speech problems were more common among the LBW children. According to the teachers' assessments at the age of 9 years, 32% of the LBW children were in need of special education, compared with 12% of the controls. A significant correlation was found between the test results at 5 years and the school achievement at the age of nine.