This paper deals with factors which influence on appearance of human error which is considered to be the most represented causal factor of marine accidents. These factors are represented within four different domains: technology, knowledge and skills of seafarers, organization and communication. Thrughout the history of marine industry there is noticeable trend of constant technological changes which have formed the entire marine system and changed the process of navigation and in that way affected all activities which may lead to human error. That's how knowledge and skills required to perform those activities, ways of communicating between members of the crew and between shipping Company and the shipping crew have changed, and in accordance with that, different models of organizational structure have been introduced on ships. Human error is considered to be erroneous activity which stems from inadequate technological and organizational solutions, but also from man's choices and attitudes. Therefore, special attention is attached to compatibility between Ship's equipment and seafarers as users, in other words, between external and internal factors.