Adequate and continuous gas supply is the foundation of the functioning of each country's economy. The Croatian gas system is increasingly relying on natural gas imports due to the decline in domestic production. Trade in natural gas, or the lease of gas capacity in the gas system, is extremely important for every trader, while gas storage facilities are the foundation of security and flexibility of gas supply. Underground gas storage ensures good security of gas supply, and since the Underground gas storage ltd. the only underground gas storage facility in the Republic of Croatia, its role is important with the aim of providing safe and quality gas storage services for the economy and private households of all citizens of the Republic of Croatia. For this purpose, by modernizing its own plant and building a new gas storage facility which improves the technological parameters of the storage facility and the speed of gas delivery according to the needs and requirements of customers, Underground gas storage ltd. in the future it still plays an important role in the safe and quality service of delivery and supply of gas from storage for the domestic market. This paper deals with and analyzes the marketing environment from a theoretical point of view and on the example of the national storage system operator of the company Underground gas storage ltd. (PSP). Also, the external and internal environment is processed and analyzed from the theoretical aspect and on the example of PSP, and the results are analyzed and presented using the SWOT matrix. Also, by applying benchmarking, the relevant characteristics of other underground storages facilities in the surrounding countries are analyzed. From the conducted analyzes, implications and strategic guidelines from the analyzed company are derived, which may be applicable to similar companies in the energy sector and beyond.