Four F-16 jets bombed the militants' stronghold city of Raqqa, targeting command and control facilities, weapons stocks and enemy personnel, Defence Command Denmark said.
NATO member Denmark is part of the U.S.-led operation "Inherent Resolve" against Islamic State, which has declared a caliphate in parts of Iraq and Syria.
Denmark's Chief of International Air Force Missions Jan Dam told Danish media the bombings had been an "important contribution" to the coalition's work.
Denmark has flown 67 missions and dropped 93 bombs in the two countries since deployment in mid-June, the military said.
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