The club was founded in August 1948. At first they played in local
MNZ Celje league, until they qualified for the
Slovenian Republic League in 1953. Two years later, on 3 July 1955, Rudar's home stadium
Ob Jezeru was opened and the club moved to its current home. After the short crisis the club returned to the Slovenian league in 1962. For the 1974–75 season the club hired a professional coach Živko Stakič and became Slovenian champions in 1977. Rudar therefore qualified for the
Yugoslav Second League, where they played until 1982. Just before the breakup of Yugoslavia, Rudar became the Slovenian champion for the second time in 1991. After the Slovenian independence, Rudar became a regular participant in the
Slovenian PrvaLiga. They were relegated to the
Slovenian Second League in 2003 and returned for the
2005–06 season, but were instantly relegated back to second level. In the 2007–08 season they finished first and thus achieved a promotion back to the first league. The club's highest finish was third place on four occasions, the last time in 2014, when
Mate Eterović, Rudar's striker, also became league's topscorer. Their biggest success was winning the
Slovenian Cup in 1998, when they lost first game away to
Primorje, but then won 3–0 in front of home crowd in the second leg. Rudar therefore played in the last edition of
UEFA Cup Winners' Cup, where it was eliminated by
Varteks in the first round. ==Honours==