Experiments 1 and 2 investigated 3- and 4-year-olds' understanding of the intended nature of pretend behaviors by testing their ability to distinguish between involuntary behaviors and the same behaviors emitted intentionally through acts of pretend. Four-year-olds' high rate of passing showed that (1) they understood intention as a mental cause of action and (2) they construed pretend behaviors mentalistically. Experiment 3 used the same contrastive procedure to examine Lillard's contention that 4-year-olds do not understand the knowledge conditions and hence the mental representational component of pretend actions. Whereas nearly all of the 5-year-olds understood that an agent who did not know of a specific animal could not be pretending to be that animal, 4-year-olds systematically associated ignorance with pretend. On the basis of the combined findings of the present experiments, and other research showing a mentalistic understanding of pretense by the age of 3 or 4, it was concluded that the specific reasoning requirements of Lillard's tasks resulted in an underestimation of children's appreciation of the mental features of pretend.