A curriculum is generally regarded as an instructional plan that describes what, why and how students should learn. In this comparative study, we analysed the Czech and Slovak intended curricula of science subjects (physics, chemistry, biology, geography, and geology) and mathematics by comparing their national curriculum documents in terms of learning outcomes at the lower secondary level (ISCED level 2). Our analysis showed significant differences in the number of obligatory learning outcomes, which were much higher in the Slovak curriculum than in the Czech curriculum. The structure of these outcomes also differed across subjects and between countries. Nevertheless, the cognitive demands of the learning outcomes analysed using the revised Bloom's taxonomy were similar in the two countries, but metacognitive knowledge and higher-level cognitive processes were rarely represented in either. Additionally, by inductive content analysis of the Slovak curriculum document, we identified two significant groups of cross-curricular requirements, namely outcomes related to scientific inquiry and outcomes requiring working with information. Overall, these learning outcomes are underrepresented in both analysed documents (particularly in the Czech document) even though the skills that these outcomes develop are in high demand in the current context.