The availability of gas on the European market, the low price and purity of gas as an energy source influenced its increasing use in the industry of European countries at the end of the 20th century. Gas pipelines from Russia to Europe were intensively built and extended. Although Russia is not the only gas producer in Europe, due to good relations with European Unions Member States and the price of gas, it has taken the place of the main supplier. With the increased demand of gas at the beginning of the 21st century, the dependence of EU Member States on Russian gas increased. Terrorist attacks in the world on economic facilities, transport and energy infrastructure had impact on the change in the content of the concept of national security at the beginning of the 21st century. Energy security becomes part of the concept of national security and is mainly defined by meeting the needs of customers on the national market. After the Russian annexation of Crimea and the introduction of EU sanctions against Russia, the content of the concept of energy security is completely changing, because gas has become an instrument of foreign policy that Russia has begun to use to achieve its political goals. The European Union is passing new legislation that requires Member States to assess the risks that threaten the safety of the gas network and the work of operators of the onshore gas network. The aim: Investigation of the aspects and assessment of the security of the gas network in the European Union, the types, nature, and severity of the risks in supply, transport and operations of the onshore gas network operator, subsequently to present the preparation of the security protection plan of the onshore gas network operators and the measures by which the estimated risks will be avoided, transferred or reduced. The method: To determine the risk of the gas network in the European Union, the method of analysis and synthesis was used. The risk aspects identified by the analysis method are broken down into elements to determine how they affect the safety of the gas network. The knowledge gained through the synthesis method was combined in a new way and their combination enabled a new view of security and risks. The deduction method made it possible to make indirect logical conclusion about the identified risks, that is, to draw specific conclusions about how to act on the identified risks, or how to avoid, transfer or reduce them and ensure the security of the gas supply. The result: The research has shown that the biggest risks in gas supply come from single supplier, operator employees and cyber threats. Identified risks can be avoided, transferred and reduced to an acceptable level by implementing the set measures in the operator’s safety protection plan. Single supplier risk can be avoided by diversifying supply, and employee and cyber risks can be avoided and reduced by training and implementing more effective security protocols and controls. The conclusion: The assessment of risks that threaten the safety of the gas network and the work of the onshore gas network operator enabled the identification of risk, drawing up a security plan and an action plan, and raising the level of security of gas supply to a higher level in case of a sudden interruption of gas supply from Russia. A sudden interruption of supply without creating a new security plan and action plan would create negative effects on the EU economy, operators’ business, the supply of households and the quality of life of all citizens.