Background: Euthanasia is an important subject that concerns law and medicine as well as morality and religion in the 21St century. Euthanasia has become a challengeable problem in scientific arena. In some countries, legal and medical practitioners are allowed to kill those cancer patients who suffer from excessive pain while incur enormous amount of expenses for their treatments.Methods: We used 3 main sources to find Islamic views on euthanasia: First, the Islamic primary source, the Holy Quran, which is the most important and reliable source for finding Islamic perspectives. Second, traditions (hadith) which include Prophet Mohammad's and his relatives's (Imams) advices. Third, religious opinions and decrees (Fatwas) from great Muslim scholars who are called Mofti Al-Aazam in Sunni tradition and Ayatollah Al-Ozma in Shiite tradition. Results: Based on the reasons proposed in the references, it can be concluded that euthanasia is forbidden in Islamic theology; and no types of euthanasia are allowed or accepted in Islam; and any action whether voluntary or involuntary that results in euthanasia of cancer patients is considered suicide and is strongly forbidden in Islam. Conclusion: Euthanasia is purely illegal in Judaism, Christianity, and Islam. In this study, we introduced a religious law based on Islamic point of view and Emamyeh section in Islam. To investigate the sensitive issue of euthanasia in Islam, the Holy Quran as the fundamental reference of Islamic law and Sonnah as the reference of Hadith (Traditions) were studied.