A diagnosis of autism spectrum disorder (ASD) is usually taken to be permanent. In this study, 13 two-year-old children with ASD lost the diagnosis by age 4, at which time they scored within the normal range on standardized measures of cognitive and adaptive functioning. No differences were found in symptom severity, socialization, or communication between children who lost the ASD diagnosis and children who did not, but children with PDD-NOS were significantly more likely than those with full autistic disorder to move off the spectrum. The clearest distinguishing factor was motor skills at age 2. Results support the idea that some toddlers with ASD can lose their diagnosis and suggest that this is difficult to predict.