Fiorentina: Serie A strugglers sack Montella after winless streak
Defeat at his former club marked the end for the former Roma striker's tenure at Fiorentina, where he had replaced Stefano Pioli in April.
Fiorentina have sacked Vincenzo Montella for the second time after Friday's heavy home loss to Roma left them languishing down in 14th place.
The 4-1 defeat was La Viola's fifth in six Serie A games, a run that has them in danger of slipping into a relegation battle.
Montella replaced Stefano Pioli in April but failed to inspire improvement as Fiorentina finished last term without a league win beyond February 17.
The former Italy international previously led the club for three seasons from 2012 to 2015.
Fiorentina said a new head coach would be confirmed "in the coming days".
Fiorentina: "Grit and determination needed on the pitch"
"The decision was taken following a long and detailed analysis of the team's performances and results," read the club's statement.
"Given the need to rediscover the necessary grit and determination on the pitch and produce an immediate turnaround, the owners and management decided that a change of coach was the best option.
"The club would like to thank Vincenzo Montella for his efforts and commitment in recent months and we wish him every success in the next chapter of his career."