The research question to be dealt with here is, what factors cause Bank interests of conventional Banks regarded as harâm from the perspective of Islam? I conducted the method of Semantic exegesis which relates to the topic, i.e. economics. The interest system of modern economics, according to al-Qur’an and prophetic traditions, can be regarded as harâm in a condition that there is no contentment (ridlâ) in any of both sides (the Bank or the creditors), neither in direct way (i.e. the creditor does not comprehend the risk) nor in indirect way (i.e. the creditor absolutely in need of the loan). In contrary, if any of both sides has to bear the risk, the interest system will be regarded to as harâm. Findings of this research show that the int...