UPDATE 1-Sulzberger Jr to retire as NYT publisher by end of December

(Adds details on Sulzberger Jr., background on digital subscriptions)

Dec 14 (Reuters) - Arthur Sulzberger Jr. will retire as publisher of the New York Times by the end of December and will be replaced by his son A.G. Sulzberger, the New York Times Co said on Thursday.

Sulzberger Jr., 66 , who joined The Times in 1978 as a correspondent, will continue as chairman of the board, the company said.

Before joining NYT, Sulzberger Jr. worked as a reporter with The Raleigh (N.C.) Times and as the London correspondent for the Associated Press.

At The Times, Sulzberger Jr. spearheaded the transformation of the company into a digital media powerhouse with strong subscription numbers in its digital business amid declining print sales.

The Times had about 2.5 million digital subscribers, helping the newspaper publisher post better-than-expected results in recent quarters.

A.G. Sulzberger, 37, who is currently Deputy Publisher at the New York Times, will also be part of the company's board.

"My focus as publisher will be on ensuring the continued journalistic excellence and commercial success of The Times through a period of transformation for the news industry," he said in a statement.

A.G. Sulzberger worked as a reporter at The Providence Journal and The Oregonian before joining The Times' metro desk in 2009.

(Reporting by Laharee Chatterjee in Bengaluru; Editing by Sriraj Kalluvila)