Developmental differences in preschool children's abilities to communicate about basic and subordinate level semantic contrasts were examined in a referential communication situation. Twenty-four three, four, and five-year-old children communicated with children of the same age and adults about pictures' referents. Speakers talked about one picture in each of 24 pairs, 12 of which were basic level contrasts (dog/cat), and 12 of which required subordinate level contrasts (poodle/collie). Results based upon child-listener referent selection indicated (1) a significant effect of age, with four- and five-year-old children selecting more correct referents than did three-year-old children, and (2) a significant category effect, with more basic level referents being selected than subordinate level referents. There was also a significant age by category level interaction in which four- and five-year-old children correctly selected more basic level referents then did the three-year old children. Instructions to label each picture in a contrast prior to communicaton resulted in improvement in four-year-old children's communication of subordinate level contrasts. The labeling and communication strategies used by subjects were shown to be a function of age and subject, experience with the task, and contrast type. The study of the referential use of standard linguistic descriptions for basic level and subordinate level semantic contrasts indicated taxonomic differentiation of concrete objects by the children. (Author/FL)