Gross out in Berne as Young Boys fire coach
Young Boys said in a statement on their website that the club had also parted company with two of his assistants after managing only one win in their last 10 matches.
Erminio Piserchia was named interim coach for the rest of the season.
Gross, who won four league titles and the same number of Swiss Cups in a 10-year spell with FC Basel which ended in 2009, was halfway through a two-year contract.
Although they sit third in the nine-team table, Young Boys, last winners of the Swiss league in 1986, have dropped 25 points behind FC Basel, who clinched the title with five games to spare on Sunday.
(Writing by Brian Homewood; Editing by John O'Brien)