Purpose: To examine lexical knowledge in children through a fast mapping task. Method: This study compared the performance of 60 African American English-speaking and general American English-speaking children between the ages of 4 and 6 years. They were presented with a comprehension task involving the fast mapping of novel verbs in 4 different argument structures (intransitive, transitive, transfer, and complement). The fast mapping task was developed to determine how children use syntactic cues to help fix the meaning of novel verbs. Results: The results indicated that both groups of children could fast map novel verbs at a relatively equivalent level. Conclusion: The promise of fast mapping as an alternative method of measuring word knowledge in culturally and linguistically diverse populations is discussed.