The relationship between religion/Islam and nationalism/Turkishness is one of the most controversial issues in modern Turkish thought. The issue has been kept up it’s actuality from the Second Constitutional Monarchy years to the present. The discussions on religion and nationalism between Turkists and Islamists constitute one of the high tension lines of modern Turkish thought. While Islamists try to prove that nationalism is forbidden by Islam, Turkists try to demonstrate that there is no ban on this issue. Ahmet Agaoglu, who entered into various discussions with the Islamists and Ottomanists on behalf of the Turkists during the Second Constitutional Monarchy years, has worked in his texts the arguments that the nationalist tradition will constantly reproduce ın the context of the relationship between religion/Islam and nationalism/Turkishness. Texts produced by Agaoglu in the discussions with Suleyman Nazif and Babanzâde Ahmed Naim, are supremely valuable in order to understand the nationalist thought in Turkey. Agaoglu's texts were aimed at creating a compromise between Islamism and Turkism, two vital thought movements of the Constitutional Era. More deeply, Agaoglu was concerned with the question of how to define modern Turkish identity. He attempted to achieve these two goals by instilling his reformist views into Turkish nationalism. However, the relationship he established between Turkishness and Islam included severe contradictions.