The closure will affect drivers using the St. Jacques exit of the Ville-Marie expressway, as well as those travelling east along St-Jacques street.
Drivers will be forced to detour onto Décarie Boulevard, Upper-Lachine Road and Girouard Avenue.
The work had been originally scheduled to begin last July.
Workers will first move part of a sewage system located below the bridge, before the dismantling of the St-Jacques overpass starting next year, Quebec's transport ministry said.
Until the demolition starts, local traffic will be allowed on St-Jacques Street between Addington Street and Décarie Boulevard.
Pedestrians will still be able to use all of St. Jacques St. until the end of 2015.