Two experiments were conducted to test Chinese children's comprehension of count-and mass-classifiers. Participants were Chinese-speaking children ages 3 thru 8, plus 16 adults. Results cohere with the linguistic analysis that the count-mass distinction is relevant in Chinese grammar. Results also cohere with the current theory in cognitive development that the ontological constraint reflected in the count-mass distinction is available in early stages of language acquisition. (Author/VWL)