The figure of £254.8 million has been fuelled by the fast-growing Latin American and Chinese markets and by an increase in new forms of interactive communication, the group said.
Sorrell, WPP's chief executive, said that while the figures reflected "another significant improvement in activity", those for the full year should "match or surpass" those of 2004, even after the fillips provided by the US presidential election and the Olympic Games were accounted for.
"Corporate profitability is strong and spending is holding up as a result," he said.
The group's revenues rose 22 per cent to £2.5 billion, an amount boosted by the acquisition of Grey Global Group and new business from HSBC and Samsung.
Improved figures in Western Europe, a market that has been static, also contributed to the positive result.
With billings up by almost a quarter to £11.3 billion, WPP has raised its operating margin target for this year from 13.2 per cent to 13.7 per cent.
"The second quarter was stronger in France and Germany," Sorrell said.
"The UK is not as stabilised or strong. The US has not been easy."
WPP, which embraces JWT, Ogilvy & Mather, Young & Rubicam and Grey, expects to expand its China operations by a third and predicts the country will become its third-biggest market by 2008.
Meanwhile, WPP has announced plans to set up a new parent company to create more reserves and allow the group to buy back shares.