HotGroup operates a network of websites including workthing.com, planetrecruit, jobsfinancial and hotrecruit, which together carry between 30,000 and 40,000 job vacancies.
The deal follows Trinity Mirror's recent acquisitions of GAAPweb.com and Smartnewhomes.com.
Sly Bailey, chief executive Trinity Mirror, said: "We are delighted to have reached agreement with the board of HotGroup.
"We see exciting opportunities for the management and continued development of HotGroup alongside our existing recruitment advertising businesses. The acquisition is consistent with our strategy of growing Trinity Mirror's core classified franchises both on- and off-line."
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum.