Aim: To monitor the trends in prevalence of cerebral palsy (CP) by birthweight in Europe, 1980 to 2003. Method: Data were collated from 20 population-based registers contributing to the Surveillance of Cerebral Palsy in Europe database. Trend analyses were conducted in four birthweight groups: <1000g (extremely low birthweight [ELBW]); 1000 to 1499g (very low birthweight [VLBW]); 1500 to 2499g (moderately low birthweight [MLBW]); and >2499g (normal birthweight [NBW]). Results: The overall prevalence of CP decreased from 1.90 to 1.77 per 1000 live births, p<0.001, with a mean annual fall of 0.7% (95% confidence interval [CI] −0.3% to −1.0%). Prevalence in NBW children showed a non-significant trend from 1.17 to 0.89 per 1000 live births (p=0.22). Prevalence in MLBW children decreased from 8.5 to 6.2 per 1000 live births (p<0.001), but not linearly. Prevalence in VLBW children also declined from 70.9 to 35.9 per 1000 live births (p<0.001) with a mean annual fall of 3.4% (95% CI −2.4% to −4.3%). Prevalence in ELBW children remained stable, at a mean rate of 42.4 per 1000 live births. Interpretation: The decline in prevalence of CP in children of VLBW continues, and confirms that previously reported. For the first time, there is also a significant decline among those of MLBW, resulting in a significant overall decrease in the prevalence of CP.