Stereotyped repetitive behaviors occur in Gilles de la Tourette's Syndrome (GTS) and obsessive-compulsive disorder (OCD). The present study was undertaken to compare the distribution of obsessive-compulsive and Tourette-related impulsive behaviors in GTS with (+) OCD, GTS without (−) OCD, tic-free OCD, and control subjects. Fourteen GTS + OCD, 18 GTS-OCD, 21 OCD-tic, and 29 control subjects were evaluated using a semistructured interview designed to assess GTS and OCD-related repetitive behaviors. Each reported item was evaluated on the presence of anxiety and goal-directedness. This information was subsequently used to define whether the repetitive behavior was an (anxiety-related) obsession or compulsion, or a (non-anxiety-related) OC-like behavior, impulsion. GTS + OCD subjects reported more overall Tourette-related impulsions than OCD-tic subjects, i.e., more mental play, echophenomena, and touching behaviors but similar frequencies of typical obsessive-compulsive behaviors. Further, GTS + OCD subjects exhibited more overall repetitive behaviors than GTS-OCD subjects, i.e., more Tourette-related impulsions as well as more obsessive-compulsive behaviors. The distribution of symptoms is similar in GTS with and without OCD, and differs from tic-free OCD. These differences suggest that GTS with OCD constitutes a form of GTS, not of OCD, although the possibility that GTS + OCD patients constitute a subgroup distinct from GTS and from OCD can not be excluded by this phenomenological study. Specific non-anxiety-related impulsions seem to discriminate between GTS and OCD-tic individuals. These impulsions possibly reflect differences in underlying mechanisms between GTS and OCD-tics.