Ketogenic diet therapies have proven efficacy for refractory epilepsy. There are many reports of their use in the genetic developmental and epileptic encephalopathies; however, little attention has been paid as to whether the diet is also effective in individuals with an acquired structural aetiology. We observed remarkable efficacy of the diet in two patients with hypoxic-ischaemic encephalopathy. We then analysed our cases with refractory structural epilepsies of acquired origin to characterize their response to the ketogenic diet. The classical ketogenic diet was implemented with dietary ratios of 3:1 to 4.4:1. Seizure frequency at 1month, 3months, 6months, 1year, and 2years was ascertained. A responder was defined as greater than 50% seizure reduction compared to baseline. Seven of the nine patients were responders at 3months. Somewhat surprisingly we found that the ketogenic diet was effective in patients with a developmental and epileptic encephalopathy due to an acquired structural aetiology. This cohort may not be routinely considered for the ketogenic diet because of their structural and acquired, rather than genetic, basis. The ketogenic diet should be considered early in the management of patients with acquired structural encephalopathies as it can improve seizure control with the potential to improve developmental outcome. The ketogenic diet was effective in children with epilepsy associated with an acquired structural aetiology.