The publisher has bought TotallyLegal.com ltd, the owner of legal recruitment site TotallyLegal.com, and TotallyFinancial.com, a recruitment site for the finance profession.
The acquisition is the latest stage in Trinity Mirror's strategy to develop its digital and online businesses through growth and acquisitions.
Chief executive Sly Bailey said the sites would complement the group's existing portfolio, which includes Secsinthecity, hotonline and a stake in Fish4jobs.