Introduction The Ages & Stages Questionnaire 3rd Edition (ASQ®-3) is a tool to measure developmental delay for children aged between 1 - 66 months originally developed in the United States. This measure has been collected in England since 2015 as a part of mandated 2-2½-year health visiting reviews and collated nationally in the Community Services Dataset (CSDS). CSDS is known to be incomplete and to-date there have not been any published analyses of ASQ®-3 held within CSDS. Objectives We aimed to a) identify a subset of complete child development data for children aged two in England using ASQ®-3 data in CSDS between 2018/19-2020/21; b) use this subset of data to analyse child development age 2-2½ years in England. Methods We compared counts of ASQ®-3 records in CSDS by local authority and financial quarter against national, publicly available health visiting metrics to identify local authorities with complete ASQ®-3 records in CSDS. We described child development in this subset of the data using both a binary cut-off of whether a child reached expected level of development and the continuous ASQ®-3 score. Results Among the 226,505 children from 64 local authorities in our sample with complete ASQ®-3 records, 86.2% met expected level of development. Children from the most deprived neighbourhoods (82.6%), children recorded as Black (78.9%), and boys (81.7%) were less likely to meet expected level of development. Conclusions To fully understand child development in England, the completeness of ASQ®-3 data in the CSDS requires improvement. Second, to interpret the national CSDS data on child development, ASQ®-3 should be standardised and validated in an English context. Developmental support is needed for at least 13.8% of the children who did not meet the expected level of development, in particular children living in the most deprived neighbourhoods, those with Black ethnicity, and boys. Key words Child development, early years, Ages and Stages Questionnaire, health visiting, Community Service Dataset