Background: In Slovakia, no relevant information is available about the scientific literacy levels achieved by secondary school students. Purpose: The objective of the research was to identify the levels of scientific literacy among students in the last year of grammar school and examine to what extent this determined the subject chosen for a school-leaving exam, which is related to a student's personal preferences, as well as to the student's profile and preparation for university education. Sample: The research sample consisted of 221 students from 17 grammar schools located in various regions of Slovakia. Design and methods: To identify the level of scientific literacy, we applied the Test of Scientific Literacy Skills. Results: The students achieved the lowest success rate in the skill focused on the identification of the research design elements and its strengths and weaknesses. A comparably low success rate was also observed in the skill focused on the justification of the conclusions based on quantitative data. Other difficulties were identified in the field of understanding the basics of statistics, thus indicating an insufficient level of mathematical literacy of the students in the abovementioned field. By contrast, the highest success rate was achieved in the skill focused on the correct application of the scientific results for social purposes. Conclusions: At the end of secondary school studies, the scientific literacy among Slovak students is at the average level. No differences were observed in terms of gender. In terms of the subjects chosen by the students for their school-leaving exams, we observed that those students who took a school-leaving exam in Biology or Chemistry achieved significantly better results in the test. By contrast, the students who reported on Geography and Civics as the subject of their school-leaving exam achieved significantly worse results in the test.