Genomic testing is being recognised as an integral part of the management of individuals with epilepsy. However, despite the increasing utility of genomic testing in epilepsy, a significant proportion of patients who are suspected to have a monogenic cause, do not receive a molecular diagnosis. Re-analysing existing genomic data increases the molecular diagnostic yield over time. As our understandings of the molecular components of epilepsy are changing faster than many other conditions, the re-analysis of existing genomic data from epilepsy patients holds significant potential in improving diagnostic outcomes.