The 1930–31 Serie B was the second tournament of this competition played in Italy since its creation.
Derthona, Lucchese, Udinese and Palermo had been promoted from Prima Divisione, while Cremonese and Padova had been relegated from Serie A.
Following a reform of the third division, the relegations were reduced from four to three.
Played in Bologna, 12 July 1931
Lucchese were relegated to Prima Divisione.