The subject of this research – constituting its final study – are the determinants of selecting a research laboratory for the needs of conducting the operational safety tests and compatibility assessment in order to issue an EC conformity declaration, as well as to voluntarily certify for a “B” safety symbol. The studies were run from the point of view of small, medium, and large manufacturing companies of agricultural machinery. The fundamental objective of this research is an attempt to reply to the question: what factors – from the point of view of the manufacturers of agricultural machinery – are relevant when selecting a research entity by them. The main objective achievement required identifying the determinants of selecting a research laboratory by the Polish manufacturer of agricultural machinery (first part of the study – research model construction), which was subject to exploration in this part of the study; theoretical model validation (assessment of the significance of requirements). Such an activity allowed for interference profiled towards the indication of a recommendation related to the way and direction of the research laboratory improvement.