Frosinone were promoted to Serie A on Friday after thumping Mantova 5-0 and joining Venezia in reaching Italy's top flight for next season.
Second place in Serie B was secured one point behind champions Venezia who also won their final match of the season, 2-0 at Palermo on Friday.
Venezia made sure of their place in Serie A last weekend.
The third and final promotion spot will come from the playoffs, with former top division outfits Monza and Palermo among the six teams in the mix.
Pisa and Verona will drop down to the second tier, with Cremonese and Lecce battling it out to stay up with three matches remaining in the season.