In Mountainous Karabagh (Nagorno Karabagh), the ARF-Dashnaktsutyun was the political party in power during the initial years of the establishment of the Republic of Mountainous Karabagh (RMK). The first president of the Supreme Council of RMK was Arthur Mkrtchyan, an ARF member.

In December 2005, the RMK President appointed ARF member, former Acting Speaker of the MKR National Assembly and member of the National Security Council, Georgi Petrossian, as Minister of Foreign Affairs.

During the July 2007 presidential elections, the ARF-Dashnaktsutyun was successful in the formation of an accord among the major political parties in RMK to support a single candidate. The candidate, Bako Sahakyan, was elected president. In the newly appointed cabinet, ARF member and former Acting Speaker of the MKR National Assembly, Georgi Petrossian was reappointed Minister of Foreign Affairs, and ARF member and former Minister of Justice, Arthur Mosiyan was appointed Chairman of the MKR Control Chamber.

In the May 23, 2010, parliamentary elections the ARF-Dashnaktsutyun garnered over 20 percent of the vote and six seats (4 through the proportional system and 2 single mandate seats) in the 33 seat (17 proportional and 16 single mandate) National Assembly.