The data and information company said the profit amounted to 56 cents per diluted share for the quarter ended Sept. 30 compared with a profit of US$369 million or 44 cents per share a year ago.
Revenue totalled US$3.22 billion, down from US$3.45 billion.
Thomson Reuters reported an adjusted profit from continuing operations of $445 million or 54 cents per share compared with $453 million or 54 cents per share a year ago.
"Third-quarter results met our expectations even as the market environment remained challenging," Thomson Reuters chief executive James Smith said in a statement.
"Our resilient subscription-based businesses performed well, while non-recurring revenues were weaker due to difficult prior-year comparables and lower transaction volumes. That said, we continue to make significant progress toward achieving our operational priorities and we remain on track to achieve our full-year outlook."
"Furthermore, despite what is anticipated to be a continued challenging environment on the top line, we expect further operational improvements to drive continued efficiencies as we work to achieve sustainable, predictable free cash flow improvement and earnings growth," Smith said.
Thomson Reuters provides specialized news, information and data for the financial, legal, accounting and science sectors.
Shares in the company were down 11 cents at C$28.32 on the Toronto Stock Exchange on Friday morning.