OBJECTIVE: To investigate which parental mental illnesses are associated with eating disorders in their offspring. METHOD: We used data from a record-linkage cohort study of 158,679 children aged 12-24 years at the end of follow-up, resident in Stockholm County from 2001 to 2007, to investigate whether different parental mental illnesses are risk factors for eating disorders in their offspring. The outcome measure was diagnosis of any eating disorder, either from an ICD or DSM-IV code, or inferred from an appointment at a specialist eating disorder clinic. RESULTS: Mental illness in parents is a risk factor for eating disorders in female offspring (Adjusted Hazard Ratio (AHR) 1.57 (95% CI 1.42, 1.92), p < 0.0001). Risk of eating disorders is increased if there is a parental diagnosis of bipolar affective disorder (AHR 2.28 (95% CI 1.39, 3.72), p = 0.004), personality disorder (AHR 1.57 (95% CI 1.01, 2.44), p = 0.043) or anxiety/depression (AHR 1.57 (95% CI 1.32, 1.86), p < 0.0001). There is a lack of statistical evidence for an association with parental schizophrenia (AHR 1.41 (95% CI 0.96, 2.07), p = 0.08), and somatoform disorder (AHR 1.25 (95% CI 0.74, 2.13), p = 0.40). There is no support for a relationship between parental substance misuse and eating disorders in children (AHR 1.08 (95% CI 0.82, 1.43), p = 0.57). DISCUSSION: Parental mental illness, specifically parental anxiety, depression, bipolar affective disorder, and personality disorders, are risk factors for eating disorders in their offspring.