Owing to e-commerce and e-government, the European Digital Single Market (DSM) is one of the most important drivers of the European economy. Due to significant changes attributable to ways of doing business in new conditions related to digital economy, a regulatory framework has been adopted that does not depend on state borders and is aimed at protecting information security and privacy. European regulations concerning personal data protection do not offer organizations an applicable process manner of harmonizing with requirements related to organizational and technical measures. Non-compliance with regulations does not only lead to legal but also to other significant consequences, such as aggravated or entirely impossible further exports to the European market. The objectives of the dissertation have been achieved, the primary research has established an intercorrelation between, respectively: (1) the understanding of the requirements prescribed by the General Data Protection Regulation (EU Regulation 2016/679) (2) the nonexistence of guidelines for harmonizing business processes with the Regulation and (3) the orientation to the European market. The obtained results indicated that the majority of respondents understood the obligations set out by the Regulation, but more than 40% of respondents required additional expert clarifications, while almost 10% of them did not understand the new obligations. Moreover, it has been revealed that organizations that apply ISO systems in their business perceive harmonizing with the Regulation as less difficult, and those that use ISO/IEC 27001, in larger amount consider it helpful in meeting the requirements specified by the Regulation. No correlation has been established between the size of the organization, the complexity of personal data processing and the perceived difficulty of harmonizing with the Regulation but significant are the indicators where almost two thirds of respondents is achieving some revenue from the exports to EU market. At the same time, almost one third of respondents believe that their organizations will increase the share of the operating revenue with EU countries in the current year, although they have not yet harmonized their business with the Regulation to the fullest extent. Moreover, it has been revealed that organizations that apply ISO systems in their business perceive harmonizing with the Regulation as less difficult and consequently, the official EU documents regarding standardisation and harmonisation in the conditions of digital transformation have been analyzed as well as preffered ISO standards of information security and privacy for the purpose of system and data protection identified. Based on their methodology, a model has been developed to represent an applicable general framework for the structured establishment, harmonization and compliance audit of organizational and technical measures with the Regulation and the national Act on the implementation of Regulation and/or controls of the ISO/IEC 27001 and ISO/IEC 27701 management system