The Quebec-based bank said its quarterly profits dropped to $28.3 million, or 91 cents per share, from $30 million, or $1.06 per share, a year earlier.
On an adjusted basis, which filters out the one-time expenses, profit increased 13 per cent to $39.8 million, or $1.31 per share, which was two cents below analyst expectations, according to a survey by Thomson Reuters.
Revenue grew 14 per cent to $221 million from $193.8 million.
The bank said it booked $14.6 million in higher expenses related to the integration of AGF Trust and the MRS Companies operations, including the IT systems, employee relocation costs and salaries.
Laurentian noted that its provision for loan losses, or the money set aside to cover bad loans, increased to $9 million from $7.5 million a year earlier.
"We continued to deliver solid revenues and earnings in the third quarter and leveraged our acquisitions to expand the Bank's revenue base," said president and CEO Rejean Robitaille.
"In an environment of slower consumer loan demand and continued margin pressure, we are working diligently to increase the value in each of our business segments."
Gross impaired loans were $98.2 million, down from $156.4 million, as of July 31.
Return on equity was 8.1 per cent, down from 10.1 per cent for the same period in 2012.
Shares of Laurentian were down 48 cents to $44.47.