The Sicilian club said in a statement that Sannino, the first Serie A coach to fall this term, would be replaced by Gian Piero Gasperini who has been out of coaching since he was fired after five games by Inter Milan at the start of last season.
Palermo took their first point of the season in a 1-1 draw at home to Cagliari on Saturday but the writing was on the wall for Sannino when the famously volatile Palermo president Maurizio Zamparini said he was worried.
"I prefer to get drunk than answer that," he told reporters when asked if Sannino was at risk. "I will watch the game again, but I am worried...I am worried we're going to get relegated."
Palermo employed three coaches last season included Devis Mangia who was hired on an interim basis, given a long-term contract after some good early results and fired six weeks later.
"I thank Zamparini for the chance he has given me," Sannino told local media. "I hoped to have more time to work, but that's football."
There were 19 coaching changes in Serie A last season.