There has been much policy interest on the theme of children's services in recent years. For example, the 1998 National Child Strategy explicitly aims to ensure good quality, affordable childcare for children aged 0 to 14 in every neighbourhood, including both formal childcare and support for informal arrangements. The sector has a changed a lot in recent years and a there are a range of data sets that explore aspects of how it works. This report explores and describes available data sources on the early years children's workforce, focusing particularly on childcare. We have investigated what administrative or survey data sets are available and how the data sources could be linked together. We start the report with a general introduction to what we mean by the children's workforce' and the sort of questions that could be asked. We summarise the data sets we have looked at, briefly commenting on how they could be used in research. In a detailed appendix, we discuss each of these data sets in turn, highlighting key strengths and limitations. In the core of the text, we provide an analysis of the children's workforce in the Labour Force Survey (occasionally supplemented with information from the Annual Survey of Hours and Earnings). Finally, we discuss future directions for research in this context. (Contains 5 figures, 4 tables and 29 footnotes.)