The maestro of Hungarian extraction held the baton at opera houses in Vienna, Graz, Hamburg and Berlin during his long career.
"With dismay and deep sadness, the Bavarian State Opera must announce the death of Stefan Soltesz," it said late on Friday in a statement.
Soltesz died late on Friday "after a collapse while conducting 'The Silent Woman' by Richard Strauss at the National Theatre" in Munich, it said. He was 73 years old.
No details on his cause of death were immediately available.
The general director of the Bavarian State Opera, Serge Dorny, tweeted he was "deeply saddened" by Soltesz's death.
"We lose a talented conductor," he said. "I lose a good friend. My thoughts are with his wife Michaela."
Soltesz served as musical director of the state theatre of Brunswick in central Germany from 1988 to 1993 and chief conductor of the Flemish Opera in Antwerp and Ghent from 1992 to 1997, followed by engagements in the western German city of Essen.
He debuted on the Bavarian State Opera stage in 1995.