The Catalan minnows have struggled to adapt to the rigours of the Primera Liga following their promotion last term and the club's board opted to axe Sampedro after Sunday's defeat to Mallorca.
"With the bad results of the team we need a swift solution and the best thing is a change on the bench," said Nastic president Jose Maria Andreu.
"This news is sad because Luis Cesar has worked very well but this is the law of football."
Luis Cesar joined Nastic in 2004 and led them to a momentous promotion last season, but he has paid the price for the poor start - with the club currently bottom of the table.
Nastic are looking to make a swift appointment, although it has not yet emerged who is the frontrunner to replace Sampedro.
Sampedro's number two Kiko Ramirez and fitness coach Xavier Bartolo will take charge of team affairs on a temporary basis.
Who do you think are likely candidates to take over? 
