Preschoolers' vocabularies are an important component of their receptive and expressive language skills. This study was designed to catalog preschoolers' expressive vocabularies to provide an accurate estimate of how many words and which words seven preschoolers knew. In this study a LENA digital recorder was used to record language samples of the children (age range 40 months to 69 months) over 4-6 days. Their language samples were transcribed and individual root words were extracted. The children spoke an average of 1,698 unique words (range 1,522 \u2014 1,957 words). There were 539 words produced by all of the children in the study as well as 820 words produced by 6 of the 7 children. These data provide preliminary information that will be useful for designing a larger, more comprehensive study of children's vocabulary with the goal of teachers and speech-language pathologists being able to use this information to determine if a child's vocabulary is smaller than other children when they enter elementary school. This can inform assessment and intervention decisions as well as provide guidance to preschool curriculum developers.