Background and aims: Theoretical background and previous data provide some similarities between problematic gambling and eating behaviors, and a theoretically increased clinical severity in individuals suffering from both conditions. However, large datasets are lacking, and therefore, the present study aimed to study, in a nationwide register material, psychiatric comorbidity, age and gender in gambling disorder (GD) patients with or without eating disorder (ED). Methods: Diagnostic data from a nationwide register were used, including all individuals with a GD diagnosis in specialized health care in Sweden, in the years 2005-2016 (N 5 2,099). Patients with GD and an ED diagnosis (n 5 57) were compared to GD patients without ED. Results: Patients with GDţED were significantly more likely than other GD patients to also have a diagnosis of drug use disorder, depressive disorders, bipolar disorders, other mood disorder, anxiety disorders, personality disorders, and neuropsychiatric disorders, when controlling for gender. In logistic regression, a comorbid ED in GD was associated with female gender, younger age, depressive disorder and personality disorders. Discussion and conclusion: In nationwide register data, despite the low number of GDţED patients, GD patients with ED appear to have a more severe psychiatric comorbidity than GD patients without ED. The combined GDţED conditions may require particular screening and clinical attention, as well as further research in larger and longitudinal studies.