Contemporary economic entities function in various types of cooperation systems, which are primarily aimed at creating a competitive advantage and strengthening themselves in order to meet the requirements of competitors. One solution that can make a significant difference to one’s market advantage is outsourcing. It is a response of enterprises to the constantly changing conditions of functioning in a turbulent environment and the emerging new directions and concepts in management. It should be stressed that the choice of outsourcing as a strategy means not only to outsource selected work to external entities, but first of all to retain those competencies of the company that cannot be replaced by anyone. This means that a company must retain a certain sphere of the so-called key areas of activity, which in a positive way distinguish it from the competition and allow it to build an effective market advantage. The main objective of the article is to identify the areas of operation that are the most common subject of outsourcing and the determinants that affect the choice of an outsourcing operator in manufacturing companies in Poland. The variety of aspects of the research subject matter, oscillating around the main objective, has made it necessary to formulate the following research hypotheses: Research Hypothesis H1—The basic criteria determining the selection of an outsourcing operator are: price, quality of services provided and reputation; Research Hypothesis H2—The most common subject of outsourcing is finance and security. The survey was conducted in 2020, in the pre-pandemic period, on a sample of N = 120, including owners/managers of manufacturing enterprises. A non-random sample selection was used. The questionnaires were sent to 200 companies, however, only 126 were completed, of which 6 were not completed in full and were therefore rejected. The verification of the hypothesis was carried out using the chi-square test.