The 1945–46 Italian Football Championship, officially known as 1945–46 Divisione Nazionale, was the first tournament held after World War II.

Wartime disruptions and US occupation of Northern Italy forced to divide the Serie A championship in two sections, North and South.

Campionato Alta Italia Serie A Just after the Allied disbandment of the fascist Higher Directory, the major clubs from US-occupied Northern Italy replaced it by a provisional football league, the High Italy League (Lega Alta Italia), which organized the local section of the Serie A. Modena and Brescia had been promoted from Serie B. Sampierdarenese and Andrea Doria reborn from Liguria and both joined this championship as FIGC special guests to repair their forced fusion by the fascist government in 1927.

Palermo had been relegated to Serie C but the FIGC annulled the move for wartime reasons.

Salernitana had been promoted from Serie C. Pisa was granted of a special break for its huge wartime damages.