Introduction. An analysis of the results of international comparative studies showed that the use of experimental tasks in the educational process ensures that students achieve higher levels of science literacy. The research purpose is to study the technology of designing experimental tasks for the development of students’ science literacy to improve teachers’ professional competencies in the field of monitoring, control and evaluation of the quality of students’ educational achievements, taking into account modern international standards. Methods. Theoretical methods included as follows: content analysis of scientific and methodological literature on the formation of students’ science literacy; generalization of the analysis of results of Russian schoolchildren’s participation in international studies. Observation, pedagogical experiment and questioning were used as empirical methods. When developing diagnostic tools, the structure of teachers’ professional competencies was considered as a combination of three components: knowledge, skills and practical experience. Statistical processing of the results of the pedagogical experiment was carried out using the sign test (G-criterion). The study involved 102 teachers from educational institutions of the Perm Krai (Russian Federation). Research results. A technology for designing experimental tasks for the development of students’ science literacy was developed and tested, and a typology of experimental tasks was described. The results of the pedagogical experiment on testing the task design technology revealed the development of a cognitive component of teachers’ professional competencies (with a significance level α=5% Gemp<Gcr, 47<72). All participants in the experiment demonstrated a positive trend in the development of the ability to analyze PISA tasks and correlate them with the main components of science literacy (with a significance level α=5% Gemp<Gcr, 65<102). Conclusion. The conducted research makes it possible to draw a conclusion about the effectiveness of the developed approaches to the design of experimental tasks. Using the design technology, teachers can prepare formative and summative assessment tasks for the systematic development of students’ science literacy.