Karakol, the principal underground group established by Nationalist Turks in Istanbul, which was under the British occupation, conducted intelligence collection and aided the covert transfer of weapons from military warehouses to Mustafa Kemal’s forces, as well as the movement of discharged military officers and personnel from Istanbul to Anatolia. Karakol was established in October 1918. It emerged as a secret security and resistance group from among the members of the dissolved Committee of Union and Progress (CUP). Karakol eventually turned into a secret organization that supported the War of Independence that started in Anatolia. Its branches worked independently and were organized according to a seven-person cell system. The names of members were unknown; each was identified by a number. The names of Executive Committee members were confidential, and the relationships of the Executive Committee with government departments, public authorities, foreigners, the press, political parties, and other individuals were run by five delegates. This paper will show the connection between the Special Organization (Teşkilat-ı Mahsusa) and the Karakol and how the leaders and the members of the CUP have organized the resistance in Istanbul and in Anatolia. Karakol played an important role in the appointment of Mustafa Kemal as the Inspector (chief) of the Ninth Army Troops Inspectorate to reorganize the remaining Ottoman military units and to improve security in Anatolia. Despite ongoing concerns about the former CUP members in Istanbul, Karakol’s connections helped Mustafa Kemal secure assignment without interference by the occupying powers. Turkish nationalists smuggled weapons and members of Special Organization into Anatolia to initiate local resistance, operating under the names of Kuvay-ı Milliye (National Forces) and Müdafaa-i Hukuk (Defense of Law). In the majority of unoccupied towns in Anatolia, the former offices of the CUP changed their names to Müdafaa-i Hukuk. After Mustafa Kemal’s arrival in Anatolia, the various national resistance movements quickly turned into a centralized structure. This paper will focus on the role of the CUP in organizing the Nationalist movement under the leadership of Mustafa Kemal.