Turkish Abstract: Turk siyasal hayatina damgasini vuran en onemli gelismelerden birisi; ulkenin kurucu ideolojisinin temsilcisi olan Cumhuriyet Halk Partisi’nde 1960’li yillarda yasanan siyasal metamorfoz surecidir. 1953 yili itibariyle bir muhalefet partisi olarak ozgurlukcu soylemlere yonelen CHP, 1965 yilinda yeni bir ideolojik kimlik ile “Ortanin Solu” soylemini benimsemistir. CHP’nin bu zamana kadarki gerceklestirmeye calistigi demokratik gelisim ve siyasi konjonkturun etkisiyle ortaya cikan bu siyasi metamorfoz sureci; 1965 secimlerinden once tartisilmaya baslanmis ve parti ici ve parti disi bircok tartismayi da beraberinde getirmistir. Acilimin tartisilmasiyla birlikte baslayan siyasal metamorfoz; Ortanin Solu ekibinin Merkez Yonetim Kurulu’na hâkim olmasi ile beraber ivme kazanmistir. Zaman icerisinde Ortanin Solu’na iliskin tartismalar parti ici iktidar mucadelesine donusurken bu surec esnasinda parti ici ve parti disi muhalefet, cesitli gruplar ile birlikte Ortanin Solu hareketine karsi etkinligini arttirmistir. Parti icindeki; ‘’Sekizler’’, ‘’Ortanin Gobekcileri’’, ‘’Ucuncu Dunyacilar’’, ‘’Sosyalist-Marksist Sol’’ gibi gruplar ile hiziplesme mucadelesi veren ‘’Ortanin Solu’’, parti disindan sol fraksiyondaki TIP ve Yon’un, sag fraksiyondan ise ozellikle Adalet Partisi’nin elestirilerine maruz kalmistir. English Abstract: One of the most significant developments that marked the Turkish political life in the 1960s was the process of political metamorphosis and in the Republican People’s Party, the representative of the constitutive ideology of the country. CHP, which ran to libertarian speech as an opposition party beginning from 1953, adopted “Middle Left” as a new ideological definition in 1965. This political metamorphosis process, which emerged with the effect of the democratic development and political conjuncture that the CHP has so far tried to achieve; It started to be discussed before the 1965 elections and brought many discussions both inside and outside the party. Political metamorphosis, which started with the discussion of discourse; It gained momentum with the Mid-Left team, which dominated the Central Board of Directors. While the discussions on the Left of the Center turned into a power struggle within the party, the internal and external opposition increased their effectiveness against the Middle Left movement with various groups. The Left of the Center, struggled with groups such as the Eights, the Hubs of the Middle, the Third Worldists, the Socialist-Marxist Left. And it, on the other hand, outside the party, the left wing was criticized by the TIP and Yon and the right wing Justice Party.