Subject of this final paper is the IGF Code and use of LNG as ship's fuel (with reference to the required additional training of ship engineers required by regulation V/3 of the STCW Convention). The structure of the paper consists of six interconnected parts. The first part of the paper is the Introduction in which the subject of the paper is presented. The second part of the paper entitled General presents the properties, hazards, transport and types of liquefied natural gas, firefighting, the impact of LNG on the environment, safety and operation, obstacles and uncertainties, simulation training and LNG-related operations and types of propupulsion engines powered by LNG. The thrid part of the paper, entitled International Regulations presents the most important regulations and conventions that are closely related to the use of LNG. The fourth part of the paper, entitled Mandatory Minimum Requirements for The Training and Qualification of Captains, Officers, Ratings and Other Personnel on Ships Subject to the IGF Regulations, presents proposals, basic and advanced training, certification, minimum training and qualification requirements for seafarers and additional training related to seafarers serving on ships subject to the IGF Regulations. In the fifth part of the paper it is discussed about the paper. The sixth part of the paper is a Conclusion in which the findings and conclusions reached during the writing of the paper are presented. Keywords: reliquefaction,