The presumption of law and consequent burden of proof has significant bearing on the length of any litigation and also on the outcome of the litigation. Just to indicate the crucialness of aforesaid legal expressions, whereas a presumption of law has the effect of shifting the burden of proof, a misplaced burden of proof may frustrate the whole trial and may result in miscarriage of justice. In this write up the aforesaid legal expressions is dealt with special reference to presumption of law in respect of negotiable instruments like Bills of exchange, promissory Notes, Cheque etc. First I will try to import the concept of presumption of law; then burden of proof; and then will apply both these expressions to negotiable instruments. It is necessary to analyze what are the rule about the rebuttable and irrebuttable presumption of law really means. Presumption of law Presumption of law implies the presumption of existence or the absence of a fact which is al