This is a cross-cultural study of the development of three components of the concept of death: Universality, Irreversibility, and Nonfunctionality. Two hundred and sixty-two Chinese and 215 U.S. children were interviewed individually using a standard interview schedule. Universality was understood at an early age by virtually all children in both cultures, as expected. However, the children's understanding of Irreversibility and Nonfunctionality varied with both culture and age: overall a greater percentage of Chinese than U.S. children gave the presumed mature adult response to each of these components; within both cultures this percentage decreased with age, rather than increasing as predicted by traditional theories of children's concept development. The children's explanation for their responses suggest that with increasing age children of both cultures develop a more complex but “fuzzier” conceptualization of death—one which increasingly includes both 1) Non-naturalistic and Naturalistic considerations and 2) uncertainty about the exact nature and location of the boundary between life and death. Implications for a more general understanding of how such complex “fuzzy” concepts develop and how they might be influenced by cultural and situational factors are discussed.