OBJECTIVES: To assess the association between time spent in care, the childcare energy-balance environment, and preschool-aged children's body mass index z-score (z-BMI), waist-to-height ratio (WHR) and sum of skinfold thickness (SST). DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: Children aged 3-4 years were recruited from 30 childcare centres in Cambridgeshire (UK) in 2013. MAIN OUTCOME MEASURES: Objectively measured height and weight was used to calculate z-BMI; waist circumference and height were used to generate WHR; subscapular and tricep skinfolds were used to calculate SST. Associations between childcare attendance, the nutrition, physical activity, and overall childcare environment, and three anthropometric outcomes were explored using two-level hierarchical regression models, adjusting for demographic and family based confounders. RESULTS: Valid data were available for 196 children (49% female). Time spent in care, the nutrition, physical activity and overall childcare environment were not associated with children's z-BMI, WHR and SST. CONCLUSIONS: Childcare environment and level of attendance were not associated with UK preschool-aged children's anthropometry. The childcare environment has been central to intervention efforts to prevent/reduce early childhood obesity, yet other factors, including child-level, family level, wider environmental and policy-level factors warrant substantial attention when considering obesity prevention strategies for young children