TORONTO — The Globe and Mail and 480 unionized employees reached a tentative contract agreement late Thursday, averting a strike at one of Canada's oldest and most influential newspapers.

The deal was signed just before a midnight deadline following a 15-hour session with a mediator.<

Details of the tentative agreement won't be released until a union ratification vote on Monday.

Brad Honywill, president of Local 87-M of the Communications, Energy and Paperworkers Union, said the union will recommend acceptance of the agreement.

"It was one of the more difficult sets of negotiations that I've seen and I think that reflects the changing economic times and people's attempts to grapple with that," Honywill said.<

The Globe workers' contract expired on Tuesday. They had previously given the union a strike mandate.

Last weekend, the editorial, advertising and circulation workers voted 89 per cent against a revised proposal emailed to them on Friday.

The proposal offered a five-year deal. It would have given existing employees the option to convert their defined-benefits pension plan into a defined-contribution plan -- which offers a lower payment -- or stick with their defined plan under an increased member contribution rate.

New hires would be started only in a defined contribution plan.

The offer included no annual wage increases in 2009 and 2010, 1.5 per cent in 2011, two per cent in 2012 and 2.5 per cent in 2013.

Phillip Crawley, Globe publisher and CEO, said in an interview last week that given the current economic climate, the paper believed the offer was "fair and reasonable."

Crawley had said the newspaper would continue to publish and post stories online if a contract could not be reached.

A spokesman for the newspaper said it will publish as usual on Friday, Saturday and Monday.