IntroductionAmbulatory Care Sensitive Conditions (ACSC) are conditions for which hospitalisation is thought to be avoidable with the use of effective preventive care and early disease management. The objective of this study was to estimate the rate of avoidable hospitalisations in children younger than 24 months of age participating in a Brazilian national representative survey and to identify the risk factors for such hospitalisations.MethodsWe analysed data from a cross-sectional study of 1901 children from the 2006 Brazilian National Demographic Health Survey of Women and Children (NDHS). The children’s socioeconomic, biological and maternal characteristics, nutritional status, and access to healthcare were tested; variables with p < 0.20 were selected to fit a Poisson regression.ResultsThe prevalence of avoidable hospitalisation was 11.8 % (95 % Confidence Interval [CI], 9.0, 15.2); the prevalence was higher in the Southeast (40.1 %) and Northwest (21.7 %) macro-regions. The multivariate model identified five risk factors for avoidable hospitalisation: male gender (Prevalence Ratio [PR] = 1.48, p = 0.004), low socioeconomic level (PR = 1.51, p = 0.005), children from mothers younger than 20 years of age (PR = 1.41, p = 0.031), not breastfed within the first hour of life (PR = 1.29, p = 0.034), and neonatal hospitalisation (PR = 1.66, p = 0.043).ConclusionsTo decrease the costs associated with avoidable hospitalisations, health managers and professionals should focus their efforts on providing effective primary healthcare to families of low socioeconomic levels, particularly prenatal and paediatric care, as well as encouraging breastfeeding and supporting young mothers. Strategies to improve children’s health by controlling such hospitalisations in Brazil should consider all residence areas and geopolitical macro-regions.