Objective the aim of this longitudinal study was to evaluate the impact of COVID‐19 epidemic on Eating Disorders (EDs) patients, considering the role of pre‐existing vulnerabilities. Method 74 patients with Anorexia Nervosa (AN) or Bulimia Nervosa (BN) and 97 healthy controls (HCs) were evaluated before lockdown (T1) and during lockdown (T2). Patients were also evaluated at the beginning of treatment (T0). Questionnaires were collected to assess psychopathology, childhood trauma, attachment style, and COVID‐19‐related post‐traumatic symptoms. Results A different trend between patients and HCs was observed only for pathological eating behaviors. Patients experienced increased compensatory exercise during lockdown; BN patients also exacerbated binge eating. Lockdown interfered with treatment outcomes: the descending trend of ED‐specific psychopathology was interrupted during the epidemic in BN patients. Previously remitted patients showed re‐exacerbation of binge eating after lockdown. Household arguments and fear for the safety of loved ones predicted increased symptoms during the lockdown. BN patients reported more severe COVID‐19‐related post‐traumatic symptomatology than AN and HCs, and these symptoms were predicted by childhood trauma and insecure attachment. Discussion COVID‐19 epidemic significantly impacted on EDs, both in terms of post‐traumatic symptomatology and interference with the recovery process. Individuals with early trauma or insecure attachment were particularly vulnerable.