Corporate social responsibillity can be defined as a concept in which company on a voluntarily basis integrates care for social questions and environmental issues in their business activities and according to relations with all the entities: owners, shareholders, employees, consumers, suppliers, government, media and public in general. This modern business practice is applied in more and more companies throughout EU and the world. In the Republic of Croatia this concept, although relatively new, gains more interest of public and companies. Strategies of CSR are getting more popular every day because companies that implement strategies of CSR in their business activities achieve competitive advantage in relation to their competitors on the market. In order for company to behave social responsible, one must possess these four responsibillities: economic responsibillity – to be profitable; legal responsibillity – to obey law; ethical responsibillity – To be ethical; filantropic responsibillity – to be good citizen. The main goal of this research is to establish the level of application of concept of social responsibillity in company ''Brodometalurgija Ltd'' and to test how application of CSR affects competitive advantage of this company. Empirical research was carried out with questionairre with sample of 35 employees, and processed with statistical software SPSS. The results showed that none of set hypothesis can't be fully accepted, but also that there is positive correlation between corporate social responsibillity and competitive advantage.