Deliberate will be looking at political, environmental and social news angle stories for the famous annual literary festival.
The agency will use the demographic make-up of festival-goers to seed stories in the press, as well as promoting the festival's green credentials. It will also liaise with sponsors and charities in the run-up to the event.
'Due to a growing international profile for the Hay brand, we decided to appoint Deliberate PR,' said festival director Peter Florence.
The festival runs from 22 May to 1 June.