Background: The expression "health literacy as a superdeterminant of health" indicates the key role of health literacy in shaping and influencing the general health of individuals and communities. eHealth literacy (EHL), in the era of digitization of health systems, is a significant predictor of an individual's health condition, and as a determinant of health, it is important in the analysis of the health system of each country. Previous research has shown that a satisfactory level of EHL is needed in order for citizens to actively participate in making correct health decisions and participate in health care Methods and Objectives: We conducted a cross-sectional study in 8 state-owned primary healthcare (PHC) centres in the territory of the Mačva district in Western Serbia. Both qualitative and quantitative research methods were used in this study. We translated, culturally adapted, and investigated the psychometric properties of the Serbian version of the eHealth Literacy Questionnaire (eHLQ), and evaluated EHL in the PHC users in Serbia Results: A total of 475 PHC users were enrolled. The highest EHL mean scores were obtained for the understanding of health concepts and language and feel safe and in control Statistically significant differences (all P<.05) for all 7 eHLQ scores were observed for age, education, perceived material status, perceived health status, searching for health information on the internet, and occupation. Conclusions: Our results demonstrate that the Serbian version of the eHLQ can be a useful tool in the measurement of EHL. Improving eHealth literacy as a superdeterminant of health represents an important political and social goal, and is of great importance for comprehensive progress, therefore we must have an adequate instrument to assess it, as well as the availability of health technologies.