The initial description of Asperger syndrome commented on the poor handwriting and motor coordination difficulties of individuals with this condition. Early descriptions of autism do not remark upon such difficulties. Recent evidence, however, suggests that individuals with both conditions have a similar motor control impairment. Handwriting has not been formally assessed in this context. Our study compared handwriting size between individuals with autism spectrum disorder and age- and IQ-matched control subjects. Macrographia was observed among subjects with autism spectrum disorder which remained statistically significant when covaried with educational level. This finding may correlate with the anatomical abnormalities present in the cerebellum of individuals with autism spectrum disorder.