This is the first reported study of children's use of two metacognitive strategies, recollection rejection and diagnostic monitoring, to reject misinformation. Recollection rejection involves the retrieval of details that disqualify an event, whereas diagnostic monitoring involves the failure to retrieve expected details. First (n = 56, age 7 years) and third graders (n = 52, age 9 years) witnessed a staged classroom interaction involving common and bizarre accidents, were presented with misinformation about the source of these events, and took a memory test. Both age groups used recollection rejection, but third graders were more effective. There was little evidence that diagnostic monitoring influenced responses for bizarre events, potentially because these events were not sufficiently bizarre in the context of the stereotype induction.