[8] He also published an ethnographic study of Macedonia's population, which he described as consisting of Bulgarians, Turks, Albanians, Vlachs (Aromanians and Megleno-Romanians), Jews and Gypsies.

He did not approve of the untimely outbreak of the Uprising on Ilinden,[3] August 2, 1903, but he participated as the leader of a cheta (armed band),[8] of which Aromanian revolutionary Ioryi Mucitano was part.

After the Young Turks Revolution of 1908, Petrov together with writer Anton Strashimirov edited the "Kulturno Edinstvo" magazine ("Cultural Unity"), published in Thessaloniki (Solun).

In the article "The Macedonian Liberation Cause on Bulgarian Soil", published in 1902 in Sofia, Petrov revealed the differences in the revolutionary tactics of the IMRO and the SMAC and the reasons for their bad relations.

He seriously criticized the provocative activities of the SMAC leaders Ivan Tsonchev and Stoyan Mihaylovski, who took the disastrous path of starting an unprepared uprising in Macedonia.

[17] BANU rejected territorial expansion and aimed at forming a Balkan federation of agrarian states, a policy which began with a détente with Yugoslavia.

Then Petrov had to deal with the problem of Bulgarian refugees who had to leave Yugoslavia and Greece, thus incurring IMRO rightist faction leaders' hatred upon himself.

[7][23] The assassination of Gyorche Petrov complicated relations between IMRO and the Bulgarian government and produced significant dissensions in the Macedonian movement.