#INSERT type:image caption:Swindon reached last season's playoff final but have struggled this time around. END#
Lee Power, the Swindon chairman, will take temporary charge of the first team after dismissing manager Mark Cooper on Saturday.
Cooper steered Swindon to the League One playoff final last season, but a 2-0 loss at Millwall on Saturday left them without a league win in six matches and one point above the relegation zone.
The Robins have begun drawing up a shortlist for a new boss, and a club statement said former Norwich and Charlton striker Power would "definitely not be the next permanent manager."
The statement, issued on Swindon's official website, said: "The football club would like to place on record their thanks to Mark for his outstanding work ethic and commitment to the job during his two-and-a-half-year tenure.
"Mark did a fantastic job which culminated in the club reaching the League One playoff final last season.
"Unfortunately, performances and results this term have not been as good as the club had hoped for with the current squad.
"The chairman, Lee Power, thought it was time to make a change and informed Mark of his decision on Saturday night after the defeat at Millwall.
"Lee will take temporary charge of the team but will definitely not be the club's next permanent manager."
Swindon said they planned to have a new manager in place "by the end of the month."