The marketing strategy must be adopted in accordance with market conditions and in accordance with the capabilities and resources of the company. The first factors that influence the choice of marketing strategy are the size of the company and the current position of the company in the market. This paper describes the marketing strategy of HEP D.D. and research was conducted on how these marketing strategies influence public opinion. Hrvatska elektroprivreda (HEP Group) is a national energy company, which has been engaged in the production, distribution and supply of electricity for more than a century, and in the last few decades also in the distribution and supply of thermal energy and natural gas to customers. Projects that HEP D.D. carried out show that HEP has recognized that in today's market it is not enough to have a quality product or service and to do business with a profit, but reputation also has a great impact on business. Socially responsible business means meeting the social expectations of all participants in the business process and all those interested in the company's operations. HEP D.D. is a company that bases its marketing activities on socially responsible business. The goal of marketing based on sponsorships and donations in sports is to create loyal users, and according to this research, this goal has been fulfilled.