Kashf ul-Asrar is among the most important works of Imam Khomeini, which plays an important role in better understanding of his political, ideological viewpoints. This work is a response to about 30-page note in which some questions were raised about Shia beliefs. Indeed, the book is a multidimensional scientific work containing different themes in defense of ideological ideas and beliefs of Shiaism as well as some criticisms against the then ruling system of Iran and introduction of fundamentals of Islamic government. The present paper is an attempt to topically classify the sources and references used in Imam’s book. The findings of this paper indicate that a considerable spectrum of sources in different fields of Islamic sciences including rational, traditional and narrative sources as well as those dealing with religious schools of thoughts, culture, history, jurisprudence etc. have been used by the Imam.