This thesis analyzes the Western perception of the racial identity of Ottoman Turks in the nineteenth century and how Caucasian slave trade complexified the perception in question. It relies on a vast array of primary sources to demonstrate how the racialist perspective towards Ottoman Turks and Caucasian slave trade became widespread in the nineteenth century. Following the emergence of race science as a respected field, the West sought to find a definite answer to the puzzling issue of the racial identity of Ottoman Turks. Raciologists agreed that Ottoman Turks came to possess a Caucasianized physical appearance as a result of white slavery while at the same time condemning the institution of white slavery in the Ottoman Empire as proof of the cultural and racial backwardness of Ottoman Turks. The racially mixed identity of Ottoman Turks also held interest in the West and discussions around it revealed the anxieties about racial intermingling and miscegenation which arose after the rise of the abolitionist movement.