In this paper we introduce a comprehensive database of the vocabulary in reading materials used by 5 – 9 year old children in the UK. The database is available on-line and allows researchers into early reading development the possibility of rigorous control over critical characteristics of experimental stimuli such as word frequency, regularity and length, frequency of grapheme-phoneme correspondences, orthographic and phonological neighbourhoods etc. The on-line database is also a resource that can be used by practitioners with interests in literacy development and literacy instruction. It can be used to obtain characteristics for a user-generated list of words, or else to generate a list of words according to constraints specified by the user. Here we present an overview of the construction of the database, the materials entered into it, the survey of schools by which we obtained information about the books that were most likely to be used by children in each age group, and the search features available on the database website. We also discuss certain characteristics of the Vocabulary itself and compare these with those reported in an earlier non-representative database reported in Stuart, Dixon, Masterson and Gray (2003). We then present a detailed analysis of the characteristics of Vocabulary in books used in the Reception year, against the background of recent recommendations for change in the early teaching of reading. Finally, we present data showing that the database is indeed already proving a useful resource for both practitioners and researchers.