The following are the main sources of Indian Contract Law : 

(i) English common law :

Indian Mercantile law owes its origin to the English Mercantile law. The sources of English mercantile law are common law, equity law, merchant and statute law. The common law of England or the judge-made law (is the unwritten law of England that consists of Judicial decisions and customs), is the preliminary source of Indian Law.

(ii) Acts enacted by Indian Legislature :

The greater part of Indian Business / Mercantile law is legislature-enacted Acts enforced by the Indian Parliament, and these are source of law, which makes it possible to bring uniformity in Indian laws. Changes according to the demand of circumstance can be brought in Indian law effectively by legislative amendments.

(iii) Judicial decisions or Judicial precedent :

Keeping in view the present situation, the verdicts / decisions made by Supreme Court on new issues and emerging debates on them are used as examples by lower courts while taking decisions.

(iv) Customs and Trade usages :

Customs and trades become binding when certain prerequisites are fulfilled. Then the custom is recognised by courts and it becomes legal obligation. In fact, the codified law of India has given superseding powers to the customs and usages.

(v) Justice, equity and good conscience :

In absence of any rule of a statutory law or custom or personal law on a particular point arising before the courts, the courts apply the doctrine “Justice, equity and good conscience”, which means that in its substance and in circumstances, the rule of English law is applicable to Indian society and circumstances.