EN
This paper includes theoretical as well as methodological considerations concerning the measurement of the internationalization degree of companies at the early stages of their international commitment, which is true for the majority of Polish companies internationalizing their activity. It includes a review of methodological approaches concerning the measurement of the degree of internationalization and related internationalization models. These considerations constituted bases for preparing theoretical and methodological framework concerning the measurement of the degree of internationalization of firms in the initial phases of this process. An original concept was presented of an internationalization index and the results of its application to measure the internationalization degree of 274 enterprises surveyed as a part of a research project, financed by the National Science Center: "Internationalization, networking and innovativeness of enterprises - cultural conditions". The paper ends with the discussion of the scope of application of the proposed index and its limitations.