Purpose: This article describes the development of a measure, called First Mentions (FM), that can be used to evaluate the referring expressions that children use to introduce characters and objects when telling a story. Method: Participants were 377 children ages 4 to 9 years (300 with typical development, 77 with language impairment) who told stories while viewing 6 picture sets. Their first mentions of 8 characters and 6 objects were scored as fully adequate, partially adequate, inadequate, or not mentioned. Total FM scores were compared across age and language groups. Results: There were significant differences for age and language status, as well as a significant Age x Language interaction. Within each age group except age 9, children in the typical development group attained higher scores than children in the group with language impairment. Conclusion: These results suggest that the FM measure is a useful tool for identifying whether a child has a problem with introducing referents in stories.