Graham Faulkner, chief executive of the Epilepsy Society, has announced that he will retire in September after 13 years at the helm.
Faulkner, 64, is credited by the charity with steering it from its previous role as a specialist residential care centre toward being a national provider of epilepsy services and a research provider.
The charity, which employs 380 permanent staff and had an income of £17m in 2011/12, also campaigns for better social care for people with epilepsy.
"I would like to think the Epilepsy Society is now an organisation fit for the 21st century," said Faulkner. "Even in this day and age, people really don’t understand the complexity and unpredictability of the condition. Throughout our 120-year history, the Epilepsy Society has been a driver of innovation and, in the long term, the strides we are making with our research offer the best hope of finding a cure and eventually preventing epilepsy altogether."