The paper deals with the influence of project work on the achievement of young learners in the area of science and social studies. The presented results are part of a wider study, in which they were interpreted from a different angle. The goal of the wider study was to determine to what extent a higher level of knowledge acquisition in the field of science and social science can be achieved through didactic instructions within the project method. The topic of this paper is theoretical and empirical exploration of the project method efficiency on the learning achievements of young learners. From the presented research objective the research problem was posed in the form of a question: Does the project method influence the level of the learners' knowledge acquisition? In accordance with the theoretical basis and the research goal a hypothesis was defined. It refers to the assumption that the experimental group learners will show a higher level of knowledge acquisition in comparison to the control group learners. In the study participated 120 fourth grade learners. The content sample which was taught through the project method for the subject science and social studies covered the teaching topic "A look back--the past." The obtained results showed that learners who worked through the project method achieved a higher level of knowledge acquisition on the final test, in comparison to the learners who covered the content in the usual way. In other words, the results support the assumption that the application of the project method influenced the increase of the knowledge quality of learners on all levels--reproduction, understanding and application of knowledge. (A bibliography is included.)