The duty of disclosure it is a preliminary requirement to effect marine insurance contract between the assured and the underwriter. The contract of Marine Insurance is called a uberrimae fidei contract, the assured, therefore, in the law of marine insurance, shall communicate a material circumstances to the latter before the policy to be effected. As growing the maritime industries in Korea, there is forming a larger marine insurance market, accordingly, and having a wide relation with the practice of the marine insurance in England. It means that the most of the legal theories of the marine insurance would be adopted by the English Marine Insurance Case Law and M.I.A., 1906. From the viewpoint of the said this author has tried out to study what is the duty of disclosure of the marine insurance based upon the English Marine Case Law.