Asked why he resigned, Mustafaj told reporters: "Tiredness."
A former ambassador to France and a writer, Mustafaj helped Albania's efforts to improve its chances of European Union membership and backed the cause of Kosovo's ethnic Albanians seeking independence from Serbia.
Mustafaj has held the foreign minister position since September 2005.
(compiled from agency reports)
RFE/RL Balkan Report
RFE/RL Balkan Report