We examined the rates of comorbid pervasive developmental disorders in participants with Tourette syndrome. We used 7288 participants from the Tourette Syndrome International Database Consortium Registry. We found 334 (4.6%; 1 of every 22 participants) with Tourette syndrome had a comorbid pervasive developmental disorder. In participants with Tourette syndrome and comorbid pervasive developmental disorders, 98.8% had one or more comorbidities (pervasive developmental disorder was not counted) compared to 13.2% in the group of participants with Tourette syndrome only. Variables from logistic modeling that were significant predictors of Tourette syndrome and pervasive developmental disorders were: male gender; no family history of tics/Tourette syndrome; and an increased number of comorbidities (P < .001). We found rates of comorbid Tourette syndrome and pervasive developmental disorders to be increased by 13 times. Identification of differences between subgroups of patients with Tourette syndrome may increase understanding of syndromal susceptibility, severity, and outcome.