Stonefield Josephson Inc., a 35-year-old accounting firm headquartered in Century City, announced Friday that it has agreed to merge with a large New York firm.

Marcum LLP, the nation’s 15th largest accounting firm, will integrate all of Stonefield’s 150 employees into its expanding national operations and rename the outfit MarcumStonefield. Terms of the deal were not announced.

The merger, which gives Marcum a foothold in Southern California for the first time, is the firm’s fifth in just over two years following a series of deals along the East Coast.

“Marcum’s merger with Stonefield Josephson is a major step forward in our expansion strategy,” said Jeffrey Weiner, Marcum managing partner, in a statement. “Our focus (is) on combining the resources, technical expertise and sophistication of a national firm with the personal attention and specialization of a boutique.”

Stonefield, which has 48 local employees, was Los Angeles County’s 30th largest accounting firm, according to the Business Journal’s annual list, published in March.

The combined firm, which will be headquartered in New York, has 1,100 professionals and 21 offices.