Long Beach-based accounting firm Windes & McClaughry Accountancy Corp. struck a deal to merge with San Francisco-based Burr Pilger Mayer Inc.

Windes & McClaughry has four offices in Southern California, including one established in Irvine in 2005. It employs about 140 total, including 35 in Irvine. The firm ranked No. 22 on the Business Journal’s list of accounting firms, which was based on local employees and published in July.

Burr Pilger Mayer employs 410 people across six offices in the Bay Area and one in Hong Kong.

The two firms combined will have $100 million in revenue, creating the largest California-based accounting firm, according to Burr Pilger Mayer. It will have 73 shareholders, 550 employees and 11 offices.

It will be known as BPM Windes in Southern California and BPM in Northern California.

“This is the first true north-south merger of significant firms in California accounting history,” said BPM managing partner Steve Mayer in a statement.

Mayer will be the chief executive, and John Di Carlo of Windes & McClaughry will stay as managing partner overseeing the Southern California operations.

The merger is expected to be completed by January 1, 2012.