| Competition: | Prima Categoria |
| Season: | 1919–20 |
| Winners: | Internazionale 2nd title |
| Prevseason: | 1914–15 |
| Nextseason: | 1920–21 |
The 1919–20 Prima Categoria season was won by Internazionale.
It was the first championship after World War One.
Struggles between minor and major clubs continued after four years of wartime break. The planned split between two national leagues had been forgotten, and the regional FAs became the lords of the tournament, which was expanded to 48 clubs. The championship was divided in a preliminary regional phase of ten matchdays, while the following national phase was split into a semifinal round of ten matchdays and a final round between three clubs.
The main tournament was split in eight groups of six clubs. First and second clubs, together with the third teams of Piedmont, advanced to the national championship. Worst clubs had to ask for re-election.
National championship was split in three groups of six clubs. Group winners advanced to the final group of three clubs. The whole tournament consequently had twenty-two matchdays.
The experimental Southern groups had their own special regulations.
Six clubs had collapsed during the war. However, Regional FAs agreed to expand the league to 48 clubs. They variously chose to promote, re-elect, or invite clubs to fill the spots they had been granted to.
Played on October 5, 1919, in Alessandria.
Played on October 5, 1919.
All matches played on November 5, 1919, in Genoa. Three available spots.
Matches played on September 29 and October 5, 1919, in Bologna.
Atalanta, Enotria Goliardo, Grifone GC, Sampierdarenese, GS Bolognese, Pro Caserta, SPES Genova, Trevigliese and Alessandrina were admitted to the 1a Categoria.
Amatori Giuoco Calcio Torino, Pastore, Ausonia Pro Gorla, Legnano, Saronno, Varese, Pavia, Carpi, Mantova, and Nazionale Emilia had been previously added to the championship by the Regional FAs.
Played on February 2, 1920, in Novara.
Played on January 4, 1920, in Brescia.
According to season 1919-20's FIGC rules in case of two teams sharing same position a playoff should have been played. When FIGC managers were noticed of too many matches programmed not for promotion or relegation sudden decided to change rules, just because of the few referees available for those matches, and upcoming matches (lower divisions) urged to get started. Later this playoff wasn't considered for the final table.
Played on February 15, 1920, in Brescia.
Played on February 8, 1920, in Saronno.
Played on March 14, 1920, in Venice.
The National semifinals had 18 clubs: six from Piedmont and Lombardy FAs, two from the other three Regional FAs.
See main article: Football in Southern Italy in 1919–20. An experimental amatorial tournament was played in Southern Italy.
Played on 13 June 1920, in Bologna.
Livorno qualified to the National Final.
Played on 20 June 1920, in Bologna.