Talks between Caesars Windsor and Unifor Local 444 are still going on and could go through the night "if we have to", according to Unifor President Dave Cassidy.
Bargaining teams from the union and management met Tuesday and Wednesday at a Windsor hotel to negotiate a deal for 2,300 striking workers.
Workers have been on strike since April 6 after rejecting a tentative agreement recommended by their bargaining team.
Meanwhile, the casino has cancelled major concerts and all hotel bookings through the end of the May.
The last time casino employees went on strike was in 2004, lasting for 43 days before both sides reached a deal.
Wednesday is day 41 of the strike.