Purpose: The submission of a DMF is not required by law or FDA regulation, it is submitted solely at the discretion of the DMF holder. The DMF contains factual and complete information on a drug product's chemistry, manufacture, stability, purity, impurity profile, packaging, and the cGMP status of any human drug product. The present work gives the Detailed idea on how to file Drug Master File in US, EUROPE, CANADA, AUSTRALIA. Approach: A Drug Master File is a submission of information to the FDA to permit the FDA to review this information in support of a third party's submission without revealing the information to the third party. In US, DMF filing was done through NDA for drugs, ANDA for generics and BLA for Biologics. In Europe, DMF filing was done through MAA via centralized procedure for eligible products and for other products via decentralized procedure was used. In CANADA, DMF filing was done through NDS for both drugs and biologic products, where as in AUSTRALIA different application processes and regulatory requirements apply depending on the type of therapeutic goods that is applied. Findings: This gives you clear vision on how to file Drug master file in US, EUROPE, CANADA and AUSTRALIA. This paper also gives you the comparison of DMF fling procedure in the above-mentioned countries so that reader can have clear idea on how to file DMF and different concerns on DMF among the above counties. Conclusion: The DMF contains factual and complete information on a drug product's chemistry, manufacture, stability, purity, impurity profile, Packaging and the cGMP status of any Drug product for humans. The content and the format for Drug Master File is used to obtain marketing Authorization. The main objective of the DMF is to support regulatory requirements of a medicinal product to prove its quality, safety and efficacy. This helps to obtain a marketing authorization grant. Now from 2016 onwards most of the regulated countries will use eCTD or their electronic format for their DMF submission.