The aim of this study was to assess rates for tic disorders and obsessive compulsive psychopathology in families of children and adolescents with Gilles de la Tourette syndrome (TS). Diagnoses were based on the DSM III-R criteria. Obsessive compulsive psychopathology, that did not fulfill the criteria for obsessive compulsive disorder (OCD) was additionally assessed and termed obsessive compulsive symptoms (OCS). The authors hypothesized that comorbid OCD or OCS in TS patients predicts a higher familial loading with obsessive compulsive symptomatology. The study cohort included 87 patients with TS who were evaluated clinically and with the use of a structured psychiatric interview. All available parents (152/174; 87%), several sibs (49/93; 53%) and some second degree relatives (27/659; 4.1%) were also interviewed. For other first and second degree relatives the family history method was used. Familial rates for TS were clearly elevated. Rates for chronic tic disorders (CT) were considerably lower than in previous studies. Additionally, tic disorders not otherwise specified (TDNOS) were diagnosed in a substantial number of first degree (15/267; 5.6%) and second degree relatives (36/659; 5.5%). OCD in parents (4/174; 2.3%) did not occur in an above baseline rate. However, both OCD (14/87; 16.1%) and OCS (15/87; 17.2%) were frequently associated with TS in index patients. Interestingly, 10 of 16 fathers with OCS also had a tic disorder. Obsessive compulsive psychopathology clustered in families. It is concluded that genetic studies in TS could profit from adhering to a conservative diagnostic approach to both tic disorders and OCD. The familial clustering of OCS/OCD in conjunction with the elevated paternal rate for the co-occurrence of tic disorders and OCS might indicate heterogeneity of TS.