BMO set aside C$306 million for credit losses, up from C$186 million ($140.11 million), a year ago.
Royal Bank of Canada and Canadian Imperial Bank of Commerce also posted higher loan loss provisions when they reported third-quarter results last week.
Net income at the bank's domestic personal and commercial banking unit rose 1% to C$648 million, while net income at its U.S. business climbed 1% to C$368 million.
Both units were hurt by higher expenses and provisions for credit losses.
Canada's fourth-largest lender said net income rose to C$1.56 billion, or C$2.34 per share, in the third quarter ended July 31, from C$1.54 billion, or C$2.31 per share, a year earlier.
Excluding items, the bank earned C$2.38 per share. Analysts on average had expected a profit of C$2.49 per share, according to IBES data from Refinitiv.
(Reporting by C Nivedita in Bengaluru; Editing by Bernard Orr)