Self-assessment of the effectiveness of the ship safety management system is a valuable means to evaluate the performance of the company and to reach the company’s targets on fleet safety. This article introduces the fundamentals and structure of the methodological approach to self-evaluation of the effectiveness of a shipping company’s safety management system. The principal steps and elements of the methodology are discussed, such as the formulation of objectives and performance standards, data collection and analysis, assessment of outcomes and creation of an action plan aimed at enhancing the effectiveness of the safety management system, organization of the self-assessment activity, encompassing also the participation of the crew, whether of the shore-based staff, frontal constitute experts, definition of the deadlines, and assignment of responsibilities. The methodology is a method that will contribute to the objectification of the self-evaluation process and to the discovery of the weaknesses from which to build. The findings of the study can be applied to shipping companies to enhance safety and effectiveness of ships operation. In conclusion, the importance of regular use of the self-assessment methodology to improve efficiency and achieve success in the safety management system is emphasized.