The Ilinden Uprising of August 1903 was an organised revolt of the Macedonians living in the Ottoman Empire prepared and carried out by the Internal Macedonian Revolutionary Organisation.

The uprising took place in the Bitola vilayet. The rebellion in the Bitola vilayet was proclaimed on August 2 (Gregorian Calendar, which corresponded to July 20 of the Julian Calendar), 1903, St. Elias' Day, the celebration of the ascension of the Prophet Elijah to Heaven (Ilinden in Macedonian), almost two weeks ahead of schedule.

The rebellion in Macedonia affected most of the central and southwestern parts of the Bitola Vilayet receiving the support of the peasant Macedonian and Vlach population of the region. Provisional governments were established in three localities, all of them Vlach mountain villages, viz Krushevo (near Prilep), Neveska near Florina and Klisura near Kastoria. In Krushevo the insurgents proclaimed the so called Krushevo Republic under the presidency of teacher Nikola Karev.

Though the rebellion was successful, the intervention of Turkish regular army led to the dissolution of the rebels' detachments. The suppression of the uprising entailed some 15,000 victims, 70,000 homeless, over 12,000 destroyed or burnt houses and over 30,000 refugees to neighbouring Bulgaria.

By the time the rebellion had started, many of its most promising potential leaders, including Goce Delčev, had already been killed in skirmishes with the Ottomans, and the effort was quashed within eleven days. The survivors managed to maintain a semi-successful guerilla campaign against the Turks for the next few years, but its greater effect was that it persuaded the European powers to attempt to convince the Ottoman sultan that he must take a more conciliatory note toward his Christian subjects in Europe.

This led to the Murzsteg Program, by which the various powers appointed observers in Macedonia. Though little came of this, in was a motivating factor in the ensuing Balkan Wars, which split up Macedonia between a northern area under Serbian (and later Yugoslav) control, a southern area under Greece and a small northeastern one under Bulgaria.

See also

• Internal Macedonian Revolutionary Organization
• Goce Delchev
• Macedonia
• Macedonians