Background: Although family history of psychiatric disorders has often been considered potentially useful in understanding clinical presentations in patients, it is less clear what a positive gambling family history means for people with gambling disorder. We sought to understand the clinical impact of having a first-degree relative with gambling disorder in a sample of adults with gambling disorder. Methods: Data from 455 participants (aged 18-65 years) who had participated in previous pharmacological and psychotherapeutic clinical trials for gambling disorder were pooled in a secondary analysis. Demographic and clinical variables were compared between those who did versus did not have one or more first-degree relative(s) with gambling disorder. Additionally, we examined whether a family history of gambling disorder was associated with treatment outcome. Results: 223 (49.0%) participants had at least one firstdegree family member(s) with gambling disorder. In terms of clinical variables, family history of gambling disorder was significantly associated with being female, having an earlier age of gambling onset, longer duration of untreated gambling illness, a greater likelihood of developing legal problems secondary to gambling, and higher rates of alcohol use disorder in family members. Family history of gambling disorder was also associated with a greater gambling symptom improvement from pharmacotherapy. Conclusions: These results indicate that gamblers with a first-degree family member with a gambling disorder may have a unique clinical presentation and better response to treatment interventions.  Kulcsszavak: family history, gambling, addiction, treatment