Purpose: to verify the relationship between the number of correct answers in expressive and receptive vocabulary tasks and the semantic categorization abilities of children with Language Development Disorders (LDD). Methods: 22 children, of both genders, with ages between 3;1 and 5;10 years carried out three tasks: Objects Categorization Test, Expressive Vocabulary Test and Receptive Vocabulary Test. Data received statistical treatment in order to compare the general performance in the tests considered and the performances of each age group, and to verify the correlation among the tests. Results: the subjects showed better performance in the Receptive Vocabulary Test, as compared to the other two tests. The characteristic heterogeneity observed in children with LDD was also observed in this comparison. There was significant evolution with the age in the Expressive Vocabulary Test and in the Distant Cohyponym category of the Objects Categorization Test. Only the Expressive Vocabulary Test and the Receptive Vocabulary Test showed significant correlation. Conclusions: the lexical deficits showed by the subjects can be related to deficits in the semantic representation and their cognitive organization. The combination of the performances on the proposed tasks can provide important information for identifying the origin of lexical deficits.