The present study investigated the validity of the MacArthur-Bates Communicative Development Inventory (CDI) for a group of toddlers 30 months of age. Study 1 examined the concurrent validity of the CDI for a group of 38 late talkers. Significant correlations were found between the CDI and direct measures of language abilities. Study 2 used likelihood ratio analysis to determine how well the CDI sorted 100 toddlers (38 late talkers and 62 children with a history of normal language development) according to language status based on direct assessment measures. The analyses showed that the CDI was effective in identifying children with low language skills up to the 11th percentile and in identifying children with normal language skills above the 49th percentile.