Emergency services were called to the Beinn Dearg peak in Wester Ross at about 1.45pm yesterday after reports that a man had collapsed.
Police, Dundonnell Mountain Rescue and a Coastguard helicopter attended. Attempts were made to revive the victim but he died.
Police said no further details of the man would be released until his next of kin have been informed.
Beinn Dearg is the highest peak on the popular four Munros circuit.