This paper will explore the debates regarding public order and morality within the context of the regulation of prostitution in Ottoman Istanbul during and after WWI. The regulation of prostitution was not a new phenomenon in the late Ottoman Empire. There had been attempts to regulate prostitution through municipal authorities in particular districts and provinces, such as Beyo?lu, Adana, ?zmir, and Beirut, during the last quarter of the nineteenth century. However, the regulation did not include all sex workers. On the one hand, foreign sex workers found legal protection through capitulations ¬—the economic and legal concessions provided to European powers— until the unilateral annulment of capitulations in 1915. On the other hand, Ottoman authorities had been reluctant to subject Muslim sex workers within the regulation terms due to the fact that it would violate Islamic legal practices prohibiting prostitution. Therefore, Ottoman authorities primarily regulated and licensed non-Muslim sex workers who held Ottoman citizenship or foreign citizens without the legal protections. This paper examines a particular breaking point in the history of regulation of prostitution after 1915, when the Ottoman authorities gained full legal authority over regulation of foreign sex workers with the annulment of the capitulations. In addition, the Ottoman medical authorities increasingly and publicly expressed the necessity of licensing Muslim sex workers during WWI and its aftermath. This paper will particularly analyze the debates between the conservative and Islamist press, led by the authors of Sebilürre?ad, and the Ottoman medical authorities, who were predominantly the members of the General Administration of Health, regarding the regulation and licensing of Muslim sex workers in Ottoman Istanbul during the war and under occupation. While regulation of prostitution had been primarily seen as a means to reduce the spread of venereal diseases, the wartime concerns regarding the social and moral order in the Ottoman society prompted public intellectuals and medical authorities to engage with a rather “political” debate through the bodies and moralities of sex workers, predominantly of Muslim women.