Changes in the prevalence of cerebral palsy (CP) in a population of Slovenian children born between 1981 and 1990 were determined. A population-based birth-cohort study was undertaken. Seven hundred and sixty-eight children with CP (aged 5 to 14 years) were identified from the National Cerebral Palsy Register in 1995. Spastic syndromes accounted for 84.8%. Of the 768 children studied, the total prevalence of CP per 1000 live births fell significantly from 3.3 in 1981 to 2.3 in 1990. This decreasing trend was observed in children born at < or = 38 weeks of gestation and in those with a birthweight of < 1500 g, but the prevalence of CP remained fairly constant in those born at > 38 weeks of gestation and in those with a birthweight of > or = 2500 g. The results show that a statistically significant improvement in the survival rate of infants born in Slovenia between 1981 and 1990 was not accompanied by an increase in the prevalence of CP. Additionally, in the group of very-low-birthweight infants the prevalence of CP considerably decreased.