The article focuses on the process of internationalization of the firm and looks at how Polish enterprises take advantage of a strategy known as global/international sourcing, or the practice of sourcing from the global market for goods and services across geopolitical boundaries. The author examines the benefits and limitations of various forms of internationalization of the firm on foreign markets. The main aim is to show that imports are still the predominant form of internationalization of Polish companies active on foreign markets. The author also highlights the differences between the various forms of internationalization used by Polish enterprises buying goods and services abroad. The analysis also covers Polish companies operating as either subsidiaries or affiliates of multinational corporations. The research uses the computer-assisted telephone interviewing (CATI) method. The interviews were held in 2010 on a sample of 244 randomly selected medium-sized and large Polish companies from the electrical engineering sector that uses global sourcing strategies in their operations. The study showed that imports are the most common form of internationalization, used by 91.8 percent of the surveyed companies, including 96.7 percent of companies that are not subsidiaries/affiliates of foreign corporations and 87.1 percent of those companies that are subsidiaries/affiliates of multinational corporations. Equity-based forms of internationalization, such as the establishment of joint-venture companies and wholly-owned subsidiaries abroad, are used by a much larger percentage of those companies that operate in the form of subsidiaries/affiliates of foreign corporations, compared with those that are not subsidiaries/affiliates of multinational corporations. Those of the surveyed companies that are subsidiaries/affiliates of multinational corporations in Poland display a higher level of internationalization than those companies that are not subsidiaries/affiliates of foreign companies, the author says, and the former companies also tend to use more advanced forms of internationalization, including financial linkages such as joint ventures and wholly-owned subsidiaries.