The club lost patience with Di Carlo after Saturday's 3-0 defeat at AC Milan left them 19th in the 20-team table, three points adrift of safety with four matches to play.
The former Parma, Chievo and Sampdoria coach managed three wins, there draws and eight defeats in his 14-match spell in the hot seat.
"The club thanks Di Carlo for his effort, professionalism and dedication," Livorno said in a statement.
It was the 15th coaching change so far this season in Serie A with three at Catania, two each at Cagliari, Sassuolo and Livorno and one apiece at Genoa, Sampdoria, Lazio, Bologna, Chievo and AC Milan.
Nicola, 41, led Livorno out of Serie B last season.
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