TORONTO (Reuters) - Barrick Gold Corp said on Friday that Chief Executive Greg Wilkins, who has been on leave dealing with an unspecified but serious medical condition, has stepped down as president and CEO but will become the gold producer's executive vice-chairman.

Company founder and Chairman Peter Munk, the acting CEO since March 27 when Wilkins went on medical leave, will stay in the role until a successor to Wilkins is appointed.

Barrick's board has appointed a committee to conduct the search for his replacement.

"We do not have a set time frame," company spokesman Vince Borg said of the CEO search.

The change "will allow me more flexibility to look after my health on an ongoing basis," Wilkins said in a company statement.

He served as CEO from February 2003 until this past March, and oversaw Barrick's $10 billion acquisition of Vancouver, British Columbia-based miner Placer Dome in March 2006.

The deal made Barrick the world's biggest gold producer.

Since Wilkins went on medical leave, he gave a speech at the company's May annual meeting and has regularly participated in the company's operations.

"Greg is a valued adviser whose contributions since the company's inception have been immeasurable," Munk stated.

Barrick, which has 27 operating mines, has been benefiting from soaring gold prices this year, as the company's realized gold price in the first quarter was $925 an ounce, its highest ever, and sales nearly doubled to $2 billion.

It is targeting 2008 gold production of 7.6 million to 8.1 million ounces and copper production of approximately 380 million to 400 million pounds.

Barrick stock is up 14 percent so far in 2008, closing on the Toronto Stock Exchange on Friday at C$47.70.

(Reporting by Lynne Olver; editing by Rob Wilson)