Waste treatment represents a significant challenge for society and the environment, and its effective management is essential to achieve a sustainable future. This paper focuses on the sorting, analysis and composition of waste in the context of the circular economy, emphasising the established legislative aspects and separation goals in the European Union. The European Union recognises the urgent need to change the linear model of production and consumption to a circular economy in which waste production is minimised, resources are used sparingly, and product lifetime is prolonged with the environmental impact being minimised. To achieve these objectives, the EU has adopted ambitious legislation to improve waste management systems. In our paper, we will focus on key legislative aspects. We analysed how this legislation sets new targets and requirements for waste separation, introduces extended producer responsibility schemes and promotes recycling and resource recovery. As a result, we will present the implementation of the determination of the average waste composition from the perspective of the Czech Republic and selected sub-regions. This paper will contribute to the discussion on practical aspects of the circular economy and will strengthen the awareness of the necessity of efficient waste management for a sustainable future.