A study of paediatric intensive care usage and need was undertaken in the former English Northern region to define appropriate local provision in the light of apparently conflicting published evidence. It was hypothesised that daily bed need would follow a Poisson distribution. All admissions of children aged less than 15 years who required intensive care in the region were recorded retrospectively for the financial year 1993/4. The mean number of beds occupied was 11.7 per day, which is equivalent to 20.7 beds per million children per day. The distribution of numbers of beds used mirrored a Poisson distribution closely, and the predicted bed requirement to cover 95% of days in the year was in agreement with that observed. Review of recommendations for paediatric intensive care provision from other studies suggests that apparent differences arise largely from the effect of different sizes of population served, and that, when allowance is made for this, underlying rates of bed requirement are strikingly similar, with a mean of around 20 per million children per day. A formula is given for the application of this model to local populations.