This study investigated the extent and nature of changes in symptomatology in cognitively able children with autism over a 3-year period. Thirty-seven children diagnosed with an autism spectrum condition involved in an earlier study (M age = 5 years, 7 months) were followed and reassessed 3 years later (M age = 8 years, 4 months). Scores on the Social Communication Questionnaire (SCQ; M. Rutter, A. Bailey, & C. Lord, 2003) decreased significantly over time in all symptom domains but especially in the social domain, and correlational findings suggested the presence of 2 distinct developmental trajectories—social communication and repetitive behaviors—that interact across time. Furthermore, 7 children (19% of sample) made substantial changes to the extent that they failed to meet criteria on diagnostic instruments (the Autism Diagnostic Observation Schedule—Generic [ADOS-G; C. Lord, M. Rutter, P. C. DiLavore, & S. Risi, 1999] and the SCQ) 3 years later. Children showing diagnostic discontinuity were distinguishable from those who fulfilled ADOS-G criteria only in terms of the age at which they began receiving intervention. The presence of a significant proportion of children showing considerable progress over the 3-year period challenges assumptions of diagnostic continuity and highlights the potential long-term benefits of early intervention.