With a gain of 76 accounting professionals, Ernst & Young LLP became the largest accounting firm in Los Angeles County this year.

That’s according to the Business Journal’s annual ranking of accounting firms by their number of accounting professionals in Los Angeles County.

This marks the first time since 2004 that Ernst & Young tops the list, pushing aside longtime No. 1, Deloitte. That company was knocked down to No. 2.

Ernst & Young has 1,137 accounting professionals at three offices in the county – downtown Los Angeles, Century City and Westlake Village. Deloitte tallied 1,109 professionals at its downtown office

Bill Browning, managing partner at Ernst & Young, said most of the new hires work in the firm’s traditional audit and accounting practice, but the fastest growing branch of the business is the advisory service, which helps companies improve operations.

Small and medium-size private companies account for 90 percent of E&Y’s clients, a reflection of the county’s economy.

“Private businesses are our main focus in the marketplace,” he said.

Advisory service consists of consulting on issues related to but not directly connected to company balance sheets. In the L.A. market, advisory service includes supply chain management, business process improvement, security for information technology systems, and accounting for importing and exporting, Browning explained.

Third-place PriceWaterhouseCoopers LLP counts ballots for the Oscars, while runner-up Deloitte is a sponsor of the Olympics. Ernst & Young is best known for its Entrepreneur of the Year Awards. The Los Angeles office of E&Y counts ballots for the Primetime Emmys and Golden Globe Awards.

Both E&Y and Deloitte – and most firms lower on the list – reported lower payrolls this year compared with four years ago, before the economic crisis. In 2007, Deloitte had 26 percent more accounting professionals and Ernst & Young 13 percent more than they reported this year.

Michelle Kerrick, managing partner at Deloitte’s downtown office, said attrition and streamlining accounted for the lower payroll numbers.

The largest accounting firms in the nation, known in the industry as the Big Four, held the top four spots on the Business Journal’s directory. All are headquartered in New York. In the No. 5 spot was Nigro Karlin Segal & Feldstein LLP, the largest L.A.-based firm on the list.