The pair depart Spotland with the club currently positioned in 14th spot in the League Two table.
A club statement read: "Rochdale football club has today terminated the contract of the manager John Coleman and assistant manager Jimmy Bell.
"Chairman Christopher Dunphy stated the regrettable decision has been made following the club's recent run of poor form. This decision was not taken lightly and was made following extensive discussions at board level.
"The club would like to thank both John and Jimmy for all their hard work and endeavours over the last 12 months and would like to wish them well for the future.
It is understood that Rochdale wish to have a new manager in place before their clash with Cheltenham Town on Friday.