Bernard is to be replaced by Patrick Taylor, the company's deputy CEO and finance director since 1996.
Meakin was one of the founders of Wiltshire Radio -- which grew to become GWR -- 20 years ago. He became chairman in 1987 and led the group's flotation in 1988. Between 1991 and 1993, he was chairman of GWR's flagship station Classic FM.
Bernard joined GWR 18 years ago. He is also chairman of London News Radio and last year received the Sony Radio Gold Award in recognition of his long service in the industry.
Meakin said, "Having been director of GWR for 20 years and chairman for 14 years the time has come for me to hand over the reins. I would like to pay tribute to Ralph [Bernard], we have achieved a great deal together; he is the most able and respected chief executive in commercial radio and the leading spokesman of the radio industry."
Yesterday GWR posted an 8% jump in full-year pre-tax profits, but this report was muted by news that advertising had slowed by as much as 9% in April and May.