The present study investigated Mandarin-speaking children's acquisition of the polarity sensitive item renhe 'any' in Mandarin Chinese. Like its English counterpart any, renhe can be used as a negative polarity item (NPI), or as a free choice (FC) item, and both the distribution and interpretation of renhe are governed by the same syntactic and semantic constraints as English any. Using a Truth Value Judgment Task, the present study tested five-year-old Mandarin-speaking children's comprehension of FC renhe in sentences containing the modal word neng 'can', and tested children's comprehension of NPI renhe in sentences containing the temporal conjunction zai... zhiqian 'before'. Most children demonstrated knowledge of the interpretation of both FC renhe and NPI renhe despite a paucity of relevant adult input. Like adults, however, Mandarin-speaking children do not use renhe frequently in ordinary conversation, due to the availability of alternative colloquial expressions (wh-pronouns) that also convey children's intended meanings.