This research analyzed gait in toddlers and tested the hypothesis that movement can be used as an early indicator of Autistic Disorder. It was proposed that an early identification method could indicate differences in the gait of toddlers with autism as opposed to those with typical development or with mental retardation. Observational methods were applied to retrospective home videos of 42 children after 6 mo. of independent walking. In particular, the Walking Observation Scale was used, which includes 11 items that analyze gait through three axes of foot movements, arm movements, and global movements. Analysis showed different distributions for the three groups, i.e., the autistic group differed from the other two on scores for the Walking Observation Scale and each axis. After 6 mo. of independent walking, different patterns in gait among groups were evident. These results agree with recently published evidence which acknowledges the importance of movement as an early indicator for differential diagnosis of autism.