Trade and commerce are an integral part of human life; therefore, it is important to know its Islamic principles and laws. Because the principle in matters (business and trades, etc.) is that everything is halal unless there is evidence of its prohibition. Therefore, if the rules that make a business fall into the category of haram are known, halal sources of income can be easily adopted according to the Shari'ah requirements. Islamic scholars have divided haram basically into two different types; a type in which goods are obtained in return such as all illicit forms of trade and business, and the second type is the one in which wealth is obtained free of charge such as theft and usurpation etc. As this article talks about the basic principles and types of prohibited trades so it throws light just on the first type. This article, in view of the arguments of the Qur'an and Sunnah and the sayings and fatwas of the scholars and jurists, also discusses those principles that can be laid down for declaring any trade as haram. This article can play a vital role and will be considered as a great contribution to the Muslims living in Non-Islamic states.
Key words: Halal, Haram, Interest, Principles, Shari'ah Law, Sources of Income, Trade.