This graduate thesis had the task of collecting available data on recorded ship failures during ship inspections related to pollution of the marine environment. The purpose of these inspections, regulated under the Memorandum of Understanding, is to detect and disable operating of substandard ships. The data obtained were sorted according to Annex VI to the MARPOL Convention, and a comparison was made within the scope of a Memorandum by each of the Annexes. Also, all currently valid memorandums of understanding are mutually comparable on the same basis. The conclusions thus obtained provide an insight into the most common deficiencies in the prevention of pollution in world ports, revealing which standards are most often met and in which they are thus trying to achieve a better degree of compliance with the standards envisaged by law.