The ESB's chairman, Mr Billy McCann, will not seek re-election when his five-year term at the State company expires in mid-January.
Mr McCann, who joined the company's board in 1986, was appointed chairman by a Fine Gael Minister for Public Enterprise, Mr Michael Lowery.
An accountant, he previously worked as managing partner with Craig Gardner Price Waterhouse.
A statement said he believed it was time for "new blood" in the position of chairman, who will bring new ideas and a fresh approach.
ESB's board is expected to decide on options for its future ownership and strategy next month. These include flotation, as favoured by its management.
The electricity market, which was partially deregulated last February, will be fully opened to competition in 2005.
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