In May 2018 General Data Protection Regulation took effect, to which, all companies had to adjust, regardless of their size and scope of work. The process of adjustment marked, for those companies, an introduction to a new way of conducting business and certain expenses which incurred in these new conditions. General Dana Protection Regulation was designed as a set of rules which are valid for all companies that work in the Eurozone, as well as in the other parts of the world. It is of special importance to companies that conduct their business via Internet. The purpose of this master's thesis is to explain which information is considered personal information and how is this personal information processed and stored according to General Dana Protection Regulation, how do companies operate to be in line with General Dana Protection Regulation, which are some of the problems and difficulties they encounter, and what are the penalties and sanctions for non-compliance with the regulation. End goal of this master's thesis is making a conclusion about advantages and disadvantages of introduction and implementation of this regulation. Data was mostly collected by researching web pages, textbooks and scientific and professional articles, by analysis of sources of law, while a minor part of data was collected by interviewing employees in small and medium sized companies. Introduction and implementation of General Data Protection Regulation in business has brought along numerous disadvantages for companies, but even bigger advantages. Main disadvantages are huge changes in environment, high costs, the fact that consent is required for every gathering and processing of data and penalties for non-compliance with the regulation. Main advantages are simpler and fairer business, increase of transparency by companies and faith of individuals towards digital economy, economic development, greater rights of individuals and a better communication between companies and individuals. We can conclude that, despite high initial costs of investment and long-term and complex process of adjustment, benefits of introducing General Data Protection Regulation are immeasuarable for companies and the whole economy.