University Avenue in downtown Palo Alto re-opened to traffic Tuesday afternoon, Sgt. Sandra Brown said.
The street had been closed in both directions between Waverley and Bryant streets since the fire in the Walgreens building the night of July 1.
The sidewalk around the building is still be closed to pedestrians and Bryant Street between University and Hamilton avenues is one-way southbound.
The fire-damaged building is in danger of collapsing because the fire burned through the roof, which had stabilized the walls. The building has been temporarily shored up to keep it from collapsing.
Building inspectors may "red-tag" the building soon, Brown added, which means it is unsafe and needs to be demolished.